WM Recorder is the best Windows Media stream recorder. It shouldn't have problem with streams likes this using authentication, 'coz in the PRO mode it can capture packets coming to your Windows Media Player. The problem is that it can't re-stream anything.

I tried HD radio at z100.com and found mms:// URLs with URL Snooper.

You may also try to change rtsp:// onto mms://. It might work better with VLC.