Changing MIDI Output Device (SB XFi MIDI (8080))?

I've been in contact with MS Support, about that in the Windows 7 Sound panel there is no longer the ability to change MIDI Port from the internal GS Wavetable synth, and got confirmed that they've removed this, both for Vista and Windows 7"The ability to choose a different hardware or software MIDI synthesizer other than the default Microsoft GS Wavetable Synth has been removed from the user interface for audio configuration in Windows Vista/Windows 7. A different output MIDI synth or output device port can be selected only by editing the registry".I really want to select the MPU-401 compatible MIDI Port, so I can make use of my old Roland MT-32 and the old Sierra games through DOS-Box