>Has anyone figured out how to maintain the session state when using SOAP? The same code when accessed from an ASP page by just invoking a COM which deals with the session object to return the same SessionID works well for each transaction. But, when that is under SOAP, the same code returns a different SessionID for each transaction when the COM is under a Web Service.

Check this article called Managing State in XML Web Services Created Using ASP.NET:

http://msdn.microsoft.com/library/en-us/cpguide/html/cpconstatemanagementinaspnetwebservices.asp?frame=true