I had one of those years ago when I lived o/s.
I opted for the UIB 2.0 instead of the cd burner
its similar to a pci card on a pc,just remove the panel and put the new panel on with the usb and plug the flat cable into the slot inside there,
It was actually a waste and got a burner later on as it was easier to just pop the cd into my pc and do stuff,you still need the Zoom Audio File Manager to uncompress the proprierty zoom files they are saved as.
I frequented this site for heaps of info
http://www.2090.org/zoom/bbs/
Good luck on finding one,its probably cheaper to get a second hand unit that has one allready on it,plenty on ebay..postage is a killer but,pretty heavy...
If I was going to accept the postage costs ,i'd rather get a newer 24trk or something,with usb allready on it and the newer ones, the files are saved as .wav allready...
I'd hate to hear what Zoom agents here in RSA will rush you for it..LOL