If I have a schema like this:
 <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
 	<xs:element name="foo">
 		<xs:complexType>
 			<xs:sequence>
 				<xs:any processContents="skip"/>
 			</xs:sequence>
 		</xs:complexType>
 	</xs:element>
 </xs:schema>

and use it to validate a document (using MSXML) like this:
 <foo>
 	<bar xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:type="wibble"/>
 </foo>

I get the following error:
 Supplied input XML is invalid
   Reason: Type 'wibble' is not found in Schema.
   Line number: 2
   Char position: 27
   Source XML:         <bar xsi:type="wibble"/>
                                              ^

I think this is incorrect on MSXML's part. The
processingContents="skip" should skip validation, but it is reporting
a validation error because of the xsi:type attribute. Saxon had a
similar problem which was considered a bug:
http://markmail.org/message/qqovu5o73566m5xq#query:xs%3Aany%20xsi%3Atype+page:1+mid:tciyyib5zkcfbanw+state:results

Does anybody know of a workaround for this? I need an element that can
contain genuinely arbitrary well-formed XML - "any well formed XML as
long as it doesn't contain any xsi:type attributes" isn't good enough.

Many thanks,
Tom