Timeout on WebRequest

Hey,

I want to set a timeout in a httpwebrequest. The property "Timeout" seems to be ignored. Does anybody have an idea for a workaround?

My Code:

var Request = (HttpWebRequest)HttpWebRequest.Create(@"***URL***");
Request.Headers["Cache-Control"] = "no-cache";
Request.Headers["Pragma"] = "no-cache";
Request.BeginGetResponse(new AsyncCallback(BeginGetResponseCompleted), Request);