diff -r c3cec2243286 vcl/aqua/source/dtrans/DataFlavorMapping.cxx
--- a/vcl/aqua/source/dtrans/DataFlavorMapping.cxx	Thu Apr 14 17:52:51 2011 +0200
+++ b/vcl/aqua/source/dtrans/DataFlavorMapping.cxx	Wed May 11 08:37:38 2011 +0200
@@ -523,6 +523,17 @@
 	throw RuntimeException(OUString(RTL_CONSTASCII_USTRINGPARAM("AquaClipboard: Cannot create com.sun.star.datatransfer.MimeContentTypeFactory")), NULL);
 }
 
+DataFlavorMapper::~DataFlavorMapper()
+{
+    // release potential NSStrings
+    for( std::hash_map< rtl::OUString, NSString*, rtl::OUStringHash >::iterator it
+         = maOfficeOnlyTypes.begin(); it != maOfficeOnlyTypes.end(); ++it )
+    {
+        [it->second release];
+        it->second = nil;
+    }    
+}
+
 DataFlavor DataFlavorMapper::systemToOpenOfficeFlavor(NSString* systemDataFlavor) const
 {
   DataFlavor oOOFlavor;
@@ -538,22 +549,44 @@
 		}
 	} // for
 
-  return oOOFlavor;
+	// look if this might be an internal type; if it comes in here it must have
+	// been through openOfficeToSystemFlavor before, so it should then be in the map
+	rtl::OUString aTryFlavor( NSStringToOUString( systemDataFlavor ) );
+	if( maOfficeOnlyTypes.find( aTryFlavor ) != maOfficeOnlyTypes.end() )
+	{
+	    oOOFlavor.MimeType = aTryFlavor;
+	    oOOFlavor.HumanPresentableName = rtl::OUString();
+	    oOOFlavor.DataType = CPPUTYPE_SEQINT8;
+	}
+	
+	return oOOFlavor;
 }
 
 NSString* DataFlavorMapper::openOfficeToSystemFlavor(const DataFlavor& oOOFlavor) const
 {
-  NSString* sysFlavor = NULL;
-
-  for (size_t i = 0; i < SIZE_FLAVOR_MAP; i++)
+    NSString* sysFlavor = NULL;
+    
+    for (size_t i = 0; i < SIZE_FLAVOR_MAP; i++)
 	{
-	  if (oOOFlavor.MimeType.compareToAscii(flavorMap[i].OOoFlavor, strlen(flavorMap[i].OOoFlavor)) == 0)
+	    if (oOOFlavor.MimeType.compareToAscii(flavorMap[i].OOoFlavor, strlen(flavorMap[i].OOoFlavor)) == 0)
 		{
-		  sysFlavor = flavorMap[i].SystemFlavor;
+		    sysFlavor = flavorMap[i].SystemFlavor;
 		}
 	}
-
-  return sysFlavor;
+	
+	if( ! sysFlavor )
+	{
+	    std::hash_map<rtl::OUString, NSString*, rtl::OUStringHash >::const_iterator it
+	    = maOfficeOnlyTypes.find( oOOFlavor.MimeType );
+	    if( it == maOfficeOnlyTypes.end() )
+	    {
+	        sysFlavor = maOfficeOnlyTypes[ oOOFlavor.MimeType ] = OUStringToNSString( oOOFlavor.MimeType );
+	    }
+	    else
+	        sysFlavor = it->second;
+	}
+	
+	return sysFlavor;
 }
 
 NSString* DataFlavorMapper::openOfficeImageToSystemFlavor(NSPasteboard* pPasteboard) const
@@ -690,6 +723,7 @@
           
           if (str != NULL)
           {
+              [str retain];
               [array addObject: str];
           }
       }
diff -r c3cec2243286 vcl/aqua/source/dtrans/DataFlavorMapping.hxx
--- a/vcl/aqua/source/dtrans/DataFlavorMapping.hxx	Thu Apr 14 17:52:51 2011 +0200
+++ b/vcl/aqua/source/dtrans/DataFlavorMapping.hxx	Wed May 11 08:37:38 2011 +0200
@@ -37,6 +37,7 @@
 #import <Cocoa/Cocoa.h>
 #include <postmac.h>
 
+#include <hash_map>
 #include <memory>
 #include <boost/shared_ptr.hpp>
 
@@ -73,6 +74,7 @@
 	 cannot be created.
    */
   DataFlavorMapper();
+  ~DataFlavorMapper();
 
 
   /* Map a system data flavor to an OpenOffice data flavor. 
@@ -136,6 +138,7 @@
 
 private:
   ::com::sun::star::uno::Reference< ::com::sun::star::datatransfer::XMimeContentTypeFactory> mrXMimeCntFactory;
+  mutable std::hash_map< rtl::OUString, NSString*, rtl::OUStringHash > maOfficeOnlyTypes;
 };
 
 typedef boost::shared_ptr<DataFlavorMapper> DataFlavorMapperPtr_t;