Getting the app switcher button working /w an MX500

[madbiker]

So after jumping through all the threads littering the forums on the subject, I've got my MX500 working just fine, except for the app switcher (for those curious, you have to use a usb connection, not a ps/2 one, and use the evdev protocol).

Now onto my problem:
The app switcher button (I think... the one near the middle of the mouse with two little squares on it) refuses to work, and nothing shows up in xev when I push it. I couldn't see any mention of this problem in the other threads, other than a few mentions from people who couldn't get theirs to work, so I thought I'd start a new thread.

Is this button simply not supported by evdev or something? Suggestions?