Schema validation in BizTalk WCF Service

Input Validation in a service created using BizTalk WCF Service publishing wizard by "Exposing schema as WCF service" :

I created a WCF service by exposing  schema. To my surprise, the service created is happily accepting all types of messages - regardless of message format/target namespace.

I thought such service have inbuilt restrictions to accept specific type of messages - as per the schema type defined while generating the service.
But I was WRONG!! :( :(

Now what..I need to find out ways to get this done. :|

Trying for MSDN  help -

http://social.msdn.microsoft.com/Forums/en-US/a7a9d957-ea98-4c92-9b4a-5446f00eb519/validation-in-auto-generated-wcf-service?forum=biztalkgeneral