Data Processing and Security extensions.

I have Reporting Server 2005 with following extension:

- Data Processing extension;

- Security Extension with forms authentication;

And I have the following question: How can I get the user name in data processing extension after forms authentication? I need this user name to filter my data. Please help me with this problem. I think that already exist standard solution, but I couldt'n found it.

You can pass User!UserID to the data extension as a query parameter. Also, at runtime under the Report Server, HttpContext.Current.User.Identity in the data extension should return whatever LogonUser accepts as userName.