Anyone having Trackpad issues in Boot Camp?

I just recently decided to try out Windows 8 Release Preview on my iMac via Boot Camp.

After some initial annoyances (my BT keyboard and Trackpad wouldn't work after install, requiring a purchase of new USB peripherals) I got things to be up and working more or less fine. Keyboard is fine, and after some initial hesitation my Trackpad allowed itself to be seduced by Windows.

Except not really. I can control the cursor, so the inputs are definitely being detected, but for some reason Win8 refuses to recognise when I click the button. No left-click, no right-click. Nothing. It just doesn't work, and I have no idea why?

Anyone have any suggestions? FYI, I'm running Mountain Lion.