How to configure sound card for audio broadcasting via rdp?

Intention:
Windows Server 2003 should play audio files through sound card line out (Creative Soundblaster Live), audio will get broadcasted by
an fm sender (which is working properly, not part of the problem)
The sound card has just been put on that machine, and we don't have physical access, only rdp & ssh

Sound started via ssh works, but is overmodulated - and there's the problem. I cannot configure the sound settings inside a terminal
connection due to that emulated rdp sound driver taking control (tried all of the three audiomodes). Is there any chance modifying
the real sound card settings via rdp? Or, at least, a command line tool for changing volume and speaker settings?

Thanks for every hint,
Fabian

Follow up to microsoft.public.windowsnt.terminalserver.misc