createObject webservice with basic authentication

I'm trying to connect to a webservice with basic http authentication on. When I use createObject, the authentication fails. It does work through cfinvoke though. Here's the code I'm using:

    var WSoptions = {};    WSoptions["username"] = "MyUsername";    WSoptions["password"] = "MyPassword";     WS = createObject("webservice", "WSurl", WSoptions);     WSaction = WS.methodName();

When i try this code I get a 401 error. Any idea what I'm doing wrong?