Trivia note: Kurzweil synths were designed, and the company founded, by Ray Kurzweil. Yes, that Ray Kurzweil.

If the software editor controls the synth via MIDI, then it ought to be possible to build an editor in (for example) Emagic SoundDiver or Logic's Environments editor. It may be that someone has already built one. If not, you would need access to the synth's full MIDI specification and manual, and some patience

Sounds like an awesome bit of kit. I'm off to the googles.

/ETA/ the manual can be downloaded.