I hear it works properly if you wipe Shitsta off your hard disk and install Linux.
Back when I used Windows XP as my main OS I used to use a thing called "macshift"... I dunno if it works with Vista.
Macshift: Change your MAC address: The definitive free command-line MAC changing utility for Windows XP



). It's just that we don't care for Winz. As far as I'm concerned there is only one good reason to keep developing them - so we can hit 'em with the BT sledgehammer 'till the glass on the Winz logo cracks.