I am currently doing some InterOp work, primarily with the Apache Axis stack. I am also have the need to work with established schemas and WSDLs for my projects (I do believe in Contract-First
I am currently running into a couple of issues:
1) Lack of support for handling an empty instance of the anyURI data type
2) Lack of support for Substitution groups
First of all, what is the timeline for supporting these schema artifacts
Secondly, I can work around the (1) issue but (2) is a significant issue for me. How can I support substituion groups in .NET Waiting for Whidbey is NOT an option for me, so what can I do NOW in 1.1
BTW, I am familiar with Dare's article that states the following:
Q: What aspects of W3C XML Schema are not supported by the XmlSerializer during conversion of schemas to classesWhat changes in the above with Whidbey
A: The XmlSerializer does not support the following:
* Any of the simple type restriction facets besides enumeration.
* Namespace based wildcards.
* Identity constraints.
* Substitution groups.
* Blocked elements or types.
Regards,
- Anil

Schema to Code Mapping - Lack of support for certain XSD artificats?
Jimbolino
We have add some new XSD support in Whidbey, but that is not going to help you in v1.1.
I think the answer is simple and easy -- if you like programming against XML.
Just have the [WebMethod] take an XmlElement -- you can process any XML you like.