found this on another forum :
"VSTMidi and BASSMidi allow you to use VSTIs or soundfonts for midi on Windows 7/8. In particular, you can use the excellent Yamaha SYXG50 softsynth. The game still has to request the device specifically, whcih most don't do, but for games that use SDL_mixer, I made a modified version of the dll that lets you choose the device."