You probably already have the program - RealBand! You should be able to route the MIDI if it actually has MIDI output. It's hard to determine if it does do this or not based on your description. Can you send the MIDI somewhere besides the program's own internal synth? If so, just port it to RealBand. Then look at the Event List on the recorded MIDI and see what is there to manipulate.

If you can't break out the MIDI from the generative app, then you might have to resort to using Jack or the like. http://jackaudio.org/