在.NET中，如何为需要身份验证的Web服务提供会话标识符？

I am using a web service that requires authentication from .NET (Visual Studio 2010). According to the documentation, you first request a session identifier from the first web service. I can do that with no problem. Then you are supposed to call the second web service for actually performing your query, passing the session identifier in a cookie. Here is my sample code: I am using a web service that requires authenti