WebClient / HttpWebRequest problem

Is there a problem with cross domain calls in beta 2? I am trying to call the youtube api which has a valid crossdomain.xml file at its root. When the code below executes I see the request for clientaccesspolicy.xml and a request for crossdomain.xml using a sniffer. The code I included below is using HttpWebRequest but I tried WebClient as well...webclient fires the completed event but the result is always empty string. Any ideas?

 
        private void buttonGetVideo_Click(object sender, RoutedEventArgs e)
        {
            HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(new Uri("http://gdata.youtube.com/feeds/api/videos/5w7i_1gDCVk"));
            request.BeginGetResponse(new AsyncCallback(ResponseCallback), request);
  &nb ...