OK. Windows Media Player 11.0 (WMP 11) does not support mms:// protocol any more. So your Vista will never play mms:// stream. Stop wasting your time on searching for a solution.
If you are using XP, you may reinstall Windows Media Player 10.0. But you won’t have chance to downgrade Vista’s WMP 11 to WMP 10.
If the mms:// stream seems to be working for your Vista, it’s not. In fact, the stream media server supports rstp:// protocol stream, and WMP try to rollover mms:// to rtsp:// or http://.
That is my conclusion after reading tons of web pages about Vista’s Media Player on mms. If my conclusion is wrong, please correct me.