Can I Dubug a web Service from the client application

Hello,
I have just written my first IIS hosted service. From WCF Test Client I can successfully run 2 services.
•      TestService
•      Login

TestService       returns “hello Pat” (just a simple test that service is working)
Login              returns a UserMaster object comprised of many values (Name, address phone etc..)

 
When I call these same two services with the same parameters through my window forms Client application ,the 1st service TestService return the correct value but the 2nd service returns just the initialized UserMaster object (ie all values set to ‘ ‘ via the constructor).

DCRulesClientSide.TransactionClient client = new DCRulesClientSide.TransactionClient();
           
            DCRulesClientSide.UserMaster MyUserDtls = client.Login(“pclarkeirl”);
            string test = client.GetData("Pat");

So the service is working , but obviously failing somewhere. I have tried to debugging the client and then step into the server code but I get “RealProxy.cs not found”.

Can some please suggest the best way to determine what is happing differently in the IIS hosted service to when it is run from WCF Test Client ? Can I debug the server application from the client and if so could you please give a detailed step by step description of how to do this ?

Regards
Pat