There are various compromises to get more buttons working
if your not fused about the red High line MFD displaying NAV and Audio then you can in fact get 10 working like the guys above have listed. (this also depends on what stereo you have)
if you tick BIT 7 (BAP communications) in one of the stereo menus with VCDS you can get 10 working, the phone button will work with the newer BT units but again no display in the High line MFD unless you buy the FIS display unit.
but if you decide to fit a set of white or colour Scirocco clocks you can have all 12 working but you'll loose the light/vision menu and the convenience menu from the white/colour display
if you still want NAV and Audio in the Red high line MFD then you only get 7 working or 8 with BT and fis display.