You can't get it because Silverlight uses a server-side technology to stream and deliver the content. You cannot grab the stream URL as you would normally do in an easy way for IceCash or Shoutcast.
IF YOU ARE FREE THIS TIME DEAR
SO I REPLY ANSER YOUR QUESTION
ABSOLUTLY ONE FOR FUN AND COME
...
http://www.rocktelevision.com/streaming/ClientBin/RockPlayer.xap
The ... "PerceivedType"="compressed"
"Content Type"="application/x-silverlight-app"
@="CompressedFolder"
[HKEY_CLASSES_ROOT.xap\ ...
