使用ASP.NET MVC进行基本身份验证

Anyone know how this works, I'm using the .net membership provider and just want to pull an xml list. I'm also using the .net mvc sdk. So here's the problem when I add the [WebApiEnabled] at the top of my controller I can successfully pull xml/json. But when I add [Authenticate] to the top of my controller I cannot login. As an example curl -i -u "admin:pass" -H "Accept: application/xml" Anyone know how this works, I'm using the .net