Impersonation in WCF

[gerom]

I need to pass specific user credentials to a .svc so it can be used to open a server.

The code in my .svc is as follows

[OperationBehavior(Impersonation = ImpersonationOption.Required)]
       public string OpenServer()
        {
RFCOMAPILib.FaxServer objFaxServer;
                NameValueCollection appSettings =   ConfigurationManager.AppSettings;
                sFAXServerName = appSettings["FAXServer"];

objFaxServer.OpenServer();
        }

When I run it from the client I get access denied. How can I pass a specific user name and password from the client to the .svc to be used to open the server connection?

Thanks

Gerom

[Frinavale]

Have you seen this Microsoft MSDN article on Delegation and impersonation with WCF?
Or this article on How to:Impersonate a Client on a Service?

-Frinny