How to access secure java webservices in .net client

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C#

C#4.0

I added java webservices using add web reference in visual studio.
I am calling in the .net client like this. But still service asking to send username password..what might be the problem???

try
            {
                //Proxy creation
               var proxy = new myservice();

                var credentials = new NetworkCredential();
                credentials.UserName = "username";
                credentials.Password = "password";

                //Credential
                proxy.Credentials = credentials;

               //Service call
                lblResponse.Text = proxy.getServerTime();
            }
            catch (Exception ex)
            {
                lblResponse.Text = ex.Message;
            }

Can anybody help me out.
Thanks.