You don't have to enter password or anything into WM Recorder. It should record Windows Media and Real video streams in PRO or ADA mode even if they are password protected ('coz it actually captures packets coming to WMP or RealPlayer).

Have you noticed what kind of streaming the used in pvt chat? Was it Windows Media, Real Video or something else?

Have you tried to get the stream URL with URL Snooper? Please PM one so that we can analyze further.