Vista - Using WCF Impersonation

I have been trying to write a very simple impersonation sample for WCF, in
which I want to show three WCF services (preferably IIS hosted) and service
A impersonating the caller and calling service B, service B impersonating a
trusted service account and calling service C. The only work the service are
doing is logging the calling identity. I am really battling and would
appreciate if you could advise on this simple scenario, using Windows
Integrated Security and simple impersonation. I do not know whether I am
getting something "small" or "major" wrong, however, I am unable to launch
any of the services once I start fiddling with configuration or setting the
Operational attributes to enfore impersonation.

Any advice and/ore comments will be highlighy appreciated.

Test program ----calls service A ---->SERVICE A (show identity of caller) --
call service B ---> SERVICE B(show identity of caller)-- call service C --->
SERVICE C(show identity of caller)
[impersonate
caller] [impersonate
trusted service account]