WPF WebBrowser Control stripping out url fragment

I am working on a control that wraps the new facebook login.  Basically, I show a wpf hosted web browser for the oath authentication page.

For example, https://graph.facebook.com/oauth/authorize?client_id=2438381916&redirect_uri=http://www.facebook.com/connect/login_success.html&type=user_agent&display=wap&req_perms=read_stream,publish_stream

When I hit this page in a regular browser, I can login and the url I land on is something like:

http://www.facebook.com/connect/login_success.html#access_token=2438381916%7C0b9c83c3e3f8a9c401363fe0-824555570%7CoURFQDTSfAKOJTlAXiO_zzlgO8c.

However, when I navigate the wpf web browser to the same url and capture the navigated after logging in.  the #access_token portion of the url is not included in e.Uri.

Is this a bug in the WPF WebBrowser control, is there any workaround?