asp.net mvc model binding

Question

Hi I am working with asp.net model binding, I have got it working previously with html forms, the problem here is the UI client is going to be a rich client.

I have this controller action

public ActionResult CreateUser(User profile)

previously with html forms, as long as the form html input names matched the name of the properties of User, model binding happens automatically, now I understand model binding also looks in route data and querystring for values to bind to an entity, but when I put querysting values that match the properties, I get a HTTP 404., in fact I cant get this actionresult to ever work. Do I need to configure a route with the parameters matching the properties of the user class.