WebService Setting Credentials

[Bob1]

Hi all,

I have a situation where I have a client calling into a webservice.
I am trying to change the security context of the client before I make the call to the webservice.

I've got something really simple like the following on the client:
// The Webservice
HelloServer.Service1 service = new Service1();
NetworkCredential testCredential = new NetworkCredential("testUser", "Password", "DOMAIN");
service.Credentials = testCredential;
service.HelloWorld();

However on the server side when I am debugging the security context of the following object:
User.Identity
It always turns out to be my windows integrated login rather than the NetworkCredential specified.

Why are these credentials not being passed throught to the web service?

Cheers for any insight into the problem.