Digest Authentication

Hi All,
I'm writing a console application that consumes a web service that uses SSL + Digest Authentication.
I'm trying to figure out how to use the digest authentication aspect of things, but I'm obviously missing something here. 

             ServiceReference1.xxxServiceSoapClient zClient = new ServiceReference1.xxxServiceSoapClient();
            try
            {
                zClient.ClientCredentials.HttpDigest.ClientCredential.UserName = IL_USER_NAME;
                zClient.ClientCredentials.HttpDigest.ClientCredential.Password = IL_PASSWORD;
       ...