I got the Olimex to work by running the updater in Vista under VMware on OSX 10.5.6 following nall’s procedure.
The little wire trick was the key.
I unplugged the device stuck the wire in, plugged it back in, connected it to VMware (it showed up as “Modem” and not as Olimex anything) and ran the updater. It enumerated as a different port (COM6) than the ISP500 does (COM3). Flipping back to OSX it shows up as a new /dev/tty.usbmodem* or /dev/cu.usbmodem*
I haven’t tried programming it yet but putting the right /dev address into avrdude’s -P parameter made it work up to “unknown status” which means theres no MCU connected (there wasn’t).