I used to have a DB50XG daughterboard that I turned into a midi module by building a psu with +-12v and +5v and a midi interface. This worked really well for about 10 years until recently when it inexplicably stopped working. I new that the SW needs to use the OS to route midi traffic to the synths, so a simple module conversion was out of the question.
I have a second Windows 7-64/i7 PC that I use for general Internet stuff (time-wasting) with a KVM switch on one of my two displays to switch between music production and time-wasting, and I couldn't bear to lose the SW so I dual booted the second PC with XP and use Midi-OX with a dual USB midi interface on the second PC to route midi traffic from two ports on my music PC to the two synths on the SW. (and breathe)
Audio is routed back from the SW to the music PC so I can record SW sounds to audio tracks. I can still use my Control Freak to do filter swells/LFO modulation etc on the XG sounds so I'm happy.