ws-trust with issuer

The more I read the more ws-trust confuses me. I I've read alot now...
Let's assume the following scenario.

I have a webbapplication that will consume a webservice. This webservice is
unsecured at the moment but should be secured by ws-trust. As a IDP we have
ADFS2 available. Is it possible to implement a ws-trust solution without
touching the webapplication? If the policy attached to the webservice uses
the "IssuedToken" and the "Issuer"-elements, does the webapplication need
any configuration at all?

Best regards
Robert