The sample Web service exposes most of the functions that are defined in the interfaces. When there is a successful login, the user object is stored in the ASP.NET session object. As a result, it is possible to call methods on the user object without passing a reference to the object back to the client of the Web service. The session state information is held in the server memory and the session key is passed back to the client in a cookie. So, if you are using a generated Web proxy client class, be sure to create a CookieContainer object and assign it to the CookieContainer property of the proxy object.
The Web service defines a separate message class. The class contains two public members (Sender and MessageText).