diff --git a/inc/caldav-PROPFIND.php b/inc/caldav-PROPFIND.php
index e3588714..a366abc5 100644
--- a/inc/caldav-PROPFIND.php
+++ b/inc/caldav-PROPFIND.php
@@ -48,7 +48,7 @@ function add_namespace( $prefix, $namespace ) {
 
 
 function ns_tag( $in_tag, $namespace=null, $prefix=null ) {
-  global $namespaces;
+  global $namespaces, $prefixes;
 
   if ( $namespace == null ) {
     // Attempt to split out from namespace:tag
@@ -65,6 +65,7 @@ function ns_tag( $in_tag, $namespace=null, $prefix=null ) {
     $tag = $in_tag;
   }
   $namespace = strtolower($namespace);
+  if ( $namespace == 'dav:' ) $namespace = 'DAV:';  // Special case for conventional naming
   $tag = strtolower($tag);
 
   if ( $prefix == null ) {
@@ -83,7 +84,7 @@ function ns_tag( $in_tag, $namespace=null, $prefix=null ) {
       }
       $i = "";
       if ( isset($prefixes[$prefix]) ) {
-        for ( $i=1; $i<20 && isset($prefixes["$prefix$i"]); $i++ ) {
+        for ( $i=1; $i<10 && isset($prefixes["$prefix$i"]); $i++ ) {
         }
       }
       if ( isset($prefixes["$prefix$i"]) ) {
@@ -100,7 +101,7 @@ function ns_tag( $in_tag, $namespace=null, $prefix=null ) {
     add_namespace( $prefix, $namespace );
   }
 
-  return $prefix . ":" . $tag;
+  return $prefix . ($prefix == "" ? "" : ":") . $tag;
 }
 
 
diff --git a/testing/tests/regression-suite/401-Cadaver-PROPFIND-1.result b/testing/tests/regression-suite/401-Cadaver-PROPFIND-1.result
index 8a43ce96..c20d0286 100644
--- a/testing/tests/regression-suite/401-Cadaver-PROPFIND-1.result
+++ b/testing/tests/regression-suite/401-Cadaver-PROPFIND-1.result
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="utf-8" ?>
-<multistatus xmlns="DAV:" xmlns:C="urn:ietf:params:xml:ns:caldav">
+<multistatus xmlns="DAV:" xmlns:C="urn:ietf:params:xml:ns:caldav" xmlns:A="http://apache.org/dav/props/">
  <response>
   <href>http://mycaldav/caldav.php/user1/home/</href>
   <propstat>
@@ -15,9 +15,9 @@
   </propstat>
   <propstat>
    <prop>
-    <executable xmlns="http://apache.org/dav/props/"/>
-    <checked-in xmlns="dav:"/>
-    <checked-out xmlns="dav:"/>
+    <A:executable/>
+    <checked-in/>
+    <checked-out/>
    </prop>
    <status>HTTP/1.1 404 Not Found</status>
   </propstat>
diff --git a/testing/tests/regression-suite/510-iCal-PROPFIND.result b/testing/tests/regression-suite/510-iCal-PROPFIND.result
index 49c31771..2ff57364 100644
--- a/testing/tests/regression-suite/510-iCal-PROPFIND.result
+++ b/testing/tests/regression-suite/510-iCal-PROPFIND.result
@@ -1,12 +1,12 @@
 HTTP/1.1 207 Multi-Status
 Date: Dow, 01 Jan 2000 00:00:00 GMT
 DAV: 1, 2, access-control, calendar-access
-ETag: "455c90fdc59860d7dfa851ad1f75b4ba"
-Content-Length: 847
+ETag: "58323b4af2f8d17c9fd4412652c18a5c"
+Content-Length: 746
 Content-Type: text/xml; charset="utf-8"
 
 <?xml version="1.0" encoding="utf-8" ?>
-<multistatus xmlns="DAV:" xmlns:C="urn:ietf:params:xml:ns:caldav">
+<multistatus xmlns="DAV:" xmlns:C="urn:ietf:params:xml:ns:caldav" xmlns:C1="http://calendarserver.org/ns/">
  <response>
   <href>/caldav.php/user1/home/</href>
   <propstat>
@@ -23,10 +23,10 @@ Content-Type: text/xml; charset="utf-8"
   </propstat>
   <propstat>
    <prop>
-    <schedule-inbox-url xmlns="urn:ietf:params:xml:ns:caldav"/>
-    <schedule-outbox-url xmlns="urn:ietf:params:xml:ns:caldav"/>
-    <dropbox-home-url xmlns="http://calendarserver.org/ns/"/>
-    <notifications-url xmlns="http://calendarserver.org/ns/"/>
+    <C:schedule-inbox-url/>
+    <C:schedule-outbox-url/>
+    <C1:dropbox-home-url/>
+    <C1:notifications-url/>
    </prop>
    <status>HTTP/1.1 404 Not Found</status>
   </propstat>
diff --git a/testing/tests/regression-suite/511-iCal-PROPFIND.result b/testing/tests/regression-suite/511-iCal-PROPFIND.result
index 35da6638..ef9a43e0 100644
--- a/testing/tests/regression-suite/511-iCal-PROPFIND.result
+++ b/testing/tests/regression-suite/511-iCal-PROPFIND.result
@@ -1,12 +1,12 @@
 HTTP/1.1 207 Multi-Status
 Date: Dow, 01 Jan 2000 00:00:00 GMT
 DAV: 1, 2, access-control, calendar-access
-ETag: "3c6167921378348411a110b1db03b7d4"
-Content-Length: 796
+ETag: "d595bef8c261fd561df6bb7eec2f3734"
+Content-Length: 659
 Content-Type: text/xml; charset="utf-8"
 
 <?xml version="1.0" encoding="utf-8" ?>
-<multistatus xmlns="DAV:" xmlns:C="urn:ietf:params:xml:ns:caldav">
+<multistatus xmlns="DAV:" xmlns:C="urn:ietf:params:xml:ns:caldav" xmlns:C1="http://calendarserver.org/ns/">
  <response>
   <href>/</href>
   <propstat>
@@ -20,11 +20,11 @@ Content-Type: text/xml; charset="utf-8"
   </propstat>
   <propstat>
    <prop>
-    <calendar-user-address-set xmlns="urn:ietf:params:xml:ns:caldav"/>
-    <schedule-inbox-url xmlns="urn:ietf:params:xml:ns:caldav"/>
-    <schedule-outbox-url xmlns="urn:ietf:params:xml:ns:caldav"/>
-    <dropbox-home-url xmlns="http://calendarserver.org/ns/"/>
-    <notifications-url xmlns="http://calendarserver.org/ns/"/>
+    <C:calendar-user-address-set/>
+    <C:schedule-inbox-url/>
+    <C:schedule-outbox-url/>
+    <C1:dropbox-home-url/>
+    <C1:notifications-url/>
    </prop>
    <status>HTTP/1.1 404 Not Found</status>
   </propstat>
diff --git a/testing/tests/regression-suite/602-Soho-PROPFIND.result b/testing/tests/regression-suite/602-Soho-PROPFIND.result
index 69528def..877fc9c1 100644
--- a/testing/tests/regression-suite/602-Soho-PROPFIND.result
+++ b/testing/tests/regression-suite/602-Soho-PROPFIND.result
@@ -1,12 +1,12 @@
 HTTP/1.1 207 Multi-Status
 Date: Dow, 01 Jan 2000 00:00:00 GMT
 DAV: 1, 2, access-control, calendar-access
-ETag: "f501a70013d679ecd57dc0981fdb62e1"
-Content-Length: 5847
+ETag: "abe3054a40d9f860fe9ccabef5e558db"
+Content-Length: 5725
 Content-Type: text/xml; charset="utf-8"
 
 <?xml version="1.0" encoding="utf-8" ?>
-<multistatus xmlns="DAV:" xmlns:C="urn:ietf:params:xml:ns:caldav">
+<multistatus xmlns="DAV:" xmlns:C="urn:ietf:params:xml:ns:caldav" xmlns:A="http://apple.com/ns/calendarserver/">
  <response>
   <href>/caldav.php/user1/</href>
   <propstat>
@@ -22,8 +22,8 @@ Content-Type: text/xml; charset="utf-8"
   </propstat>
   <propstat>
    <prop>
-    <dropbox-home-url xmlns="http://apple.com/ns/calendarserver/"/>
-    <notifications-url xmlns="http://apple.com/ns/calendarserver/"/>
+    <A:dropbox-home-url/>
+    <A:notifications-url/>
    </prop>
    <status>HTTP/1.1 404 Not Found</status>
   </propstat>
@@ -43,8 +43,8 @@ Content-Type: text/xml; charset="utf-8"
   </propstat>
   <propstat>
    <prop>
-    <dropbox-home-url xmlns="http://apple.com/ns/calendarserver/"/>
-    <notifications-url xmlns="http://apple.com/ns/calendarserver/"/>
+    <A:dropbox-home-url/>
+    <A:notifications-url/>
    </prop>
    <status>HTTP/1.1 404 Not Found</status>
   </propstat>
diff --git a/testing/tests/regression-suite/603-Soho-PROPFIND.result b/testing/tests/regression-suite/603-Soho-PROPFIND.result
index 0aa867ef..3edfc407 100644
--- a/testing/tests/regression-suite/603-Soho-PROPFIND.result
+++ b/testing/tests/regression-suite/603-Soho-PROPFIND.result
@@ -1,12 +1,12 @@
 HTTP/1.1 207 Multi-Status
 Date: Dow, 01 Jan 2000 00:00:00 GMT
 DAV: 1, 2, access-control, calendar-access
-ETag: "82a2af4a319c7702f65e131574e63754"
-Content-Length: 1261
+ETag: "461b0f96e42a2b69d256b99bc8d2ea1e"
+Content-Length: 1139
 Content-Type: text/xml; charset="utf-8"
 
 <?xml version="1.0" encoding="utf-8" ?>
-<multistatus xmlns="DAV:" xmlns:C="urn:ietf:params:xml:ns:caldav">
+<multistatus xmlns="DAV:" xmlns:C="urn:ietf:params:xml:ns:caldav" xmlns:A="http://apple.com/ns/calendarserver/">
  <response>
   <href>/caldav.php/user1/</href>
   <propstat>
@@ -22,8 +22,8 @@ Content-Type: text/xml; charset="utf-8"
   </propstat>
   <propstat>
    <prop>
-    <dropbox-home-url xmlns="http://apple.com/ns/calendarserver/"/>
-    <notifications-url xmlns="http://apple.com/ns/calendarserver/"/>
+    <A:dropbox-home-url/>
+    <A:notifications-url/>
    </prop>
    <status>HTTP/1.1 404 Not Found</status>
   </propstat>
@@ -43,8 +43,8 @@ Content-Type: text/xml; charset="utf-8"
   </propstat>
   <propstat>
    <prop>
-    <dropbox-home-url xmlns="http://apple.com/ns/calendarserver/"/>
-    <notifications-url xmlns="http://apple.com/ns/calendarserver/"/>
+    <A:dropbox-home-url/>
+    <A:notifications-url/>
    </prop>
    <status>HTTP/1.1 404 Not Found</status>
   </propstat>
diff --git a/testing/tests/regression-suite/604-Soho-PROPFIND.result b/testing/tests/regression-suite/604-Soho-PROPFIND.result
index 17697d3c..25576b7a 100644
--- a/testing/tests/regression-suite/604-Soho-PROPFIND.result
+++ b/testing/tests/regression-suite/604-Soho-PROPFIND.result
@@ -1,12 +1,12 @@
 HTTP/1.1 207 Multi-Status
 Date: Dow, 01 Jan 2000 00:00:00 GMT
 DAV: 1, 2, access-control, calendar-access
-ETag: "c240d5bc59682fd96a47d4b802052879"
-Content-Length: 689
+ETag: "f90fce514cd7d7155fcb48f704e9f171"
+Content-Length: 651
 Content-Type: text/xml; charset="utf-8"
 
 <?xml version="1.0" encoding="utf-8" ?>
-<multistatus xmlns="DAV:" xmlns:C="urn:ietf:params:xml:ns:caldav">
+<multistatus xmlns="DAV:" xmlns:C="urn:ietf:params:xml:ns:caldav" xmlns:A="http://apple.com/ns/calendarserver/">
  <response>
   <href>/caldav.php/user1/</href>
   <propstat>
@@ -22,8 +22,8 @@ Content-Type: text/xml; charset="utf-8"
   </propstat>
   <propstat>
    <prop>
-    <dropbox-home-url xmlns="http://apple.com/ns/calendarserver/"/>
-    <notifications-url xmlns="http://apple.com/ns/calendarserver/"/>
+    <A:dropbox-home-url/>
+    <A:notifications-url/>
    </prop>
    <status>HTTP/1.1 404 Not Found</status>
   </propstat>
diff --git a/testing/tests/regression-suite/820-Spec-PROPFIND-1.result b/testing/tests/regression-suite/820-Spec-PROPFIND-1.result
index 963cdd0e..00252749 100644
--- a/testing/tests/regression-suite/820-Spec-PROPFIND-1.result
+++ b/testing/tests/regression-suite/820-Spec-PROPFIND-1.result
@@ -39,10 +39,10 @@
   </propstat>
   <propstat>
    <prop>
-    <lockdiscovery xmlns="dav:"/>
-    <source xmlns="dav:"/>
-    <checked-in xmlns="dav:"/>
-    <checked-out xmlns="dav:"/>
+    <lockdiscovery/>
+    <source/>
+    <checked-in/>
+    <checked-out/>
    </prop>
    <status>HTTP/1.1 404 Not Found</status>
   </propstat>
diff --git a/testing/tests/regression-suite/821-Spec-PROPFIND-2.result b/testing/tests/regression-suite/821-Spec-PROPFIND-2.result
index 92c49000..1b3fb3c5 100644
--- a/testing/tests/regression-suite/821-Spec-PROPFIND-2.result
+++ b/testing/tests/regression-suite/821-Spec-PROPFIND-2.result
@@ -2,7 +2,7 @@ HTTP/1.1 207 Multi-Status
 Date: Dow, 01 Jan 2000 00:00:00 GMT
 DAV: 1, 2, access-control, calendar-access
 ETag: "deadbeefcafefeeddeadbeefcafefeed"
-Content-Length: 1219
+Content-Length: 1141
 Content-Type: text/xml; charset="utf-8"
 
 <?xml version="1.0" encoding="utf-8" ?>
@@ -37,12 +37,12 @@ Content-Type: text/xml; charset="utf-8"
   </propstat>
   <propstat>
    <prop>
-    <lockdiscovery xmlns="dav:"/>
-    <source xmlns="dav:"/>
-    <checked-in xmlns="dav:"/>
-    <checked-out xmlns="dav:"/>
-    <bogus-property xmlns="dav:"/>
-    <contentbogosity xmlns="dav:"/>
+    <lockdiscovery/>
+    <source/>
+    <checked-in/>
+    <checked-out/>
+    <bogus-property/>
+    <contentbogosity/>
    </prop>
    <status>HTTP/1.1 404 Not Found</status>
   </propstat>
diff --git a/testing/tests/regression-suite/822-Spec-PROPFIND-3.result b/testing/tests/regression-suite/822-Spec-PROPFIND-3.result
index 1e021b20..8176541b 100644
--- a/testing/tests/regression-suite/822-Spec-PROPFIND-3.result
+++ b/testing/tests/regression-suite/822-Spec-PROPFIND-3.result
@@ -30,10 +30,10 @@
   </propstat>
   <propstat>
    <prop>
-    <lockdiscovery xmlns="dav:"/>
-    <source xmlns="dav:"/>
-    <checked-in xmlns="dav:"/>
-    <checked-out xmlns="dav:"/>
+    <lockdiscovery/>
+    <source/>
+    <checked-in/>
+    <checked-out/>
    </prop>
    <status>HTTP/1.1 404 Not Found</status>
   </propstat>
diff --git a/testing/tests/regression-suite/826-Spec-PROPFIND.result b/testing/tests/regression-suite/826-Spec-PROPFIND.result
index b82c988d..a0aaa047 100644
--- a/testing/tests/regression-suite/826-Spec-PROPFIND.result
+++ b/testing/tests/regression-suite/826-Spec-PROPFIND.result
@@ -38,10 +38,10 @@
   </propstat>
   <propstat>
    <prop>
-    <lockdiscovery xmlns="dav:"/>
-    <source xmlns="dav:"/>
-    <checked-in xmlns="dav:"/>
-    <checked-out xmlns="dav:"/>
+    <lockdiscovery/>
+    <source/>
+    <checked-in/>
+    <checked-out/>
    </prop>
    <status>HTTP/1.1 404 Not Found</status>
   </propstat>
diff --git a/testing/tests/regression-suite/827-Spec-PROPFIND.result b/testing/tests/regression-suite/827-Spec-PROPFIND.result
index 7bb50089..9fe8cf78 100644
--- a/testing/tests/regression-suite/827-Spec-PROPFIND.result
+++ b/testing/tests/regression-suite/827-Spec-PROPFIND.result
@@ -38,10 +38,10 @@
   </propstat>
   <propstat>
    <prop>
-    <lockdiscovery xmlns="dav:"/>
-    <source xmlns="dav:"/>
-    <checked-in xmlns="dav:"/>
-    <checked-out xmlns="dav:"/>
+    <lockdiscovery/>
+    <source/>
+    <checked-in/>
+    <checked-out/>
    </prop>
    <status>HTTP/1.1 404 Not Found</status>
   </propstat>
@@ -85,10 +85,10 @@
   </propstat>
   <propstat>
    <prop>
-    <lockdiscovery xmlns="dav:"/>
-    <source xmlns="dav:"/>
-    <checked-in xmlns="dav:"/>
-    <checked-out xmlns="dav:"/>
+    <lockdiscovery/>
+    <source/>
+    <checked-in/>
+    <checked-out/>
    </prop>
    <status>HTTP/1.1 404 Not Found</status>
   </propstat>
@@ -132,10 +132,10 @@
   </propstat>
   <propstat>
    <prop>
-    <lockdiscovery xmlns="dav:"/>
-    <source xmlns="dav:"/>
-    <checked-in xmlns="dav:"/>
-    <checked-out xmlns="dav:"/>
+    <lockdiscovery/>
+    <source/>
+    <checked-in/>
+    <checked-out/>
    </prop>
    <status>HTTP/1.1 404 Not Found</status>
   </propstat>
@@ -179,10 +179,10 @@
   </propstat>
   <propstat>
    <prop>
-    <lockdiscovery xmlns="dav:"/>
-    <source xmlns="dav:"/>
-    <checked-in xmlns="dav:"/>
-    <checked-out xmlns="dav:"/>
+    <lockdiscovery/>
+    <source/>
+    <checked-in/>
+    <checked-out/>
    </prop>
    <status>HTTP/1.1 404 Not Found</status>
   </propstat>
@@ -226,10 +226,10 @@
   </propstat>
   <propstat>
    <prop>
-    <lockdiscovery xmlns="dav:"/>
-    <source xmlns="dav:"/>
-    <checked-in xmlns="dav:"/>
-    <checked-out xmlns="dav:"/>
+    <lockdiscovery/>
+    <source/>
+    <checked-in/>
+    <checked-out/>
    </prop>
    <status>HTTP/1.1 404 Not Found</status>
   </propstat>
@@ -273,10 +273,10 @@
   </propstat>
   <propstat>
    <prop>
-    <lockdiscovery xmlns="dav:"/>
-    <source xmlns="dav:"/>
-    <checked-in xmlns="dav:"/>
-    <checked-out xmlns="dav:"/>
+    <lockdiscovery/>
+    <source/>
+    <checked-in/>
+    <checked-out/>
    </prop>
    <status>HTTP/1.1 404 Not Found</status>
   </propstat>
diff --git a/testing/tests/regression-suite/843-Spec-PROPFIND.result b/testing/tests/regression-suite/843-Spec-PROPFIND.result
index 3825c211..844a2f62 100644
--- a/testing/tests/regression-suite/843-Spec-PROPFIND.result
+++ b/testing/tests/regression-suite/843-Spec-PROPFIND.result
@@ -1,17 +1,17 @@
 <?xml version="1.0" encoding="utf-8" ?>
-<multistatus xmlns="DAV:" xmlns:C="urn:ietf:params:xml:ns:caldav">
+<multistatus xmlns="DAV:" xmlns:C="urn:ietf:params:xml:ns:caldav" xmlns:R="urn:mcmillan:bogus:xml:ns:rscds">
  <response>
   <href>http://mycaldav/caldav.php/user1/home/</href>
   <propstat>
    <prop>
     <displayname>User One's Calendar</displayname>
-    <arbitrary xmlns="urn:mcmillan:bogus:xml:ns:rscds">A completely bogus property which should be saved.</arbitrary>
+    <R:arbitrary>A completely bogus property which should be saved.</R:arbitrary>
    </prop>
    <status>HTTP/1.1 200 OK</status>
   </propstat>
   <propstat>
    <prop>
-    <owner xmlns="dav:"/>
+    <owner/>
    </prop>
    <status>HTTP/1.1 404 Not Found</status>
   </propstat>
diff --git a/testing/tests/regression-suite/870-Principal-PROPFIND.result b/testing/tests/regression-suite/870-Principal-PROPFIND.result
index 68f6c38b..6072e362 100644
--- a/testing/tests/regression-suite/870-Principal-PROPFIND.result
+++ b/testing/tests/regression-suite/870-Principal-PROPFIND.result
@@ -39,10 +39,10 @@
   </propstat>
   <propstat>
    <prop>
-    <lockdiscovery xmlns="dav:"/>
-    <source xmlns="dav:"/>
-    <checked-in xmlns="dav:"/>
-    <checked-out xmlns="dav:"/>
+    <lockdiscovery/>
+    <source/>
+    <checked-in/>
+    <checked-out/>
    </prop>
    <status>HTTP/1.1 404 Not Found</status>
   </propstat>