Passthrough indentification in wcf

How do I pass the identity of the logged on user in an a webapplication to a service beein开发者_运维问答g called by the webserver?

My idea her is to set som kind of EndpointIdentity on the cahnnel. In my case this will be an GUID identifing the user's session on the webserver.

Anyone got any exprience on this.. Maybe I have misunderstood the concept?

Any idea's or links would be apriciated.

I have replied to one of the questions on Stackoverflow for a similar kind of problem:here

Please check, it will be helpful for your problem also.