访问流缓冲区HttpWebRequest

我正在尝试在Windows Phone 7应用程序中流媒体广播，为此我使用ManagedMediaHelpers。获取连续流的HttpWebRequest工作，但由于连续流而不调用回调Url。

如果没有回调Url的帮助，我如何访问流?在其他一些帖子说，O需要使用反射，但有人知道如何实现它吗?下面是我的代码:

req = (HttpWebRequest) WebRequest.Create(
    "http://streamer-dtc-aa01.somafm.com:80/stream/1018");
// if this is false it will fire up the callback Url 
// but the mediastreamsource will throw an exception 
// saying the it needs to be true
req.AllowReadStreamBuffering = true; 
IAsyncResult result = req.BeginGetResponse(RequestComplete,null);
private void RequestComplete(IAsyncResult r)
{
    HttpWebResponse resp = req.EndGetResponse(r) as HttpWebResponse;
    Stream str = resp.GetResponseStream();
    mss = new Mp3MediaStreamSource(str, resp.ContentLength);
    Deployment.Current.Dispatcher.BeginInvoke(() => {
        this.me.Volume = 100;
        this.me.SetSource(mss);
    });
}