SOAP/WSDL Authentication

Good Day All, Trying to connect to a web service to handle our company's gift card activation and when trying to instantiate a SoapClient object with the WSDL parameter, I get an HTTP Authentication failure. Warning: SoapClient::__construct(http://.../b2b.wsdl <http://.../b2b.wsdl> ) [function.--construct]: failed to open stream: HTTP request failed! HTTP/1.1 401 Unauthorized in C:\AMP\Apache2\htdocs\soap.php on line 5 I have a username and password, but I am not sure how to include it. I have tried: $client = new SoapClient(http://path/to/file.wsdl <http://path/to/file.wsdl> , array("login" => "userid", "password" => "pwd"); I keep getting the HTTP/1.1 401 Unauthorized... Any help would be greatly appreciated. Thanks Ken Vandegrift