Hi JP,

Why not to define the web service like this:

public class WebServiceTest : System.Web.Services.WebService
{
   public WebServiceTest()
   {
   }

   [WebMethod]
   public void SetCredentials( string u, string p )
   {
       Context.Cache["UserName"] = u;
       Context.Cache["Password"] = p;
   }

   [WebMethod]
   public string GetCredentials()
   {
       return Context.Cache["UserName"] + ", " + Context.Cache["Password"];
   }
}

Then you don't have to pass these username and password to every method.
You can call it in your client app like this:

   static class Program
   {
       /// <summary>
       /// The main entry point for the application.
       /// </summary>
       [STAThread]
       static void Main()
       {
           localhost.WebServiceTest test = new
WindowsApplication1.localhost.WebServiceTest();
           test.SetCredentials( "username", "password" );
           string str = test.GetCredentials();
           Console.WriteLine( str );
       }
   }