Currently it only recognizes it as an "Apple Wireless Mouse", so the mouse preferences don't show any of the MagicMouse features and of course scrolling doesn't work.

I tried installing Apple's WirelessMouseSoftware update, but it tells me that a newer version is being used. Is there something in there that I can extract using Pacifist? Is there a way to inject the MagicMouse device ID during startup? Or .....

Well, I have it working now, along with scrolling

Not sure exactly what I did, but it has to be something involving the DSDT as that is the only thing I've been working on. The only changes I can think of, that I made, involve the renaming of various labels:

LPC -> LPCB (make sure to rename all instances, including any .LPC)
TMR -> TIMR
FPU -> MATH
RTC0 -> RTC

I believe that's all I did before it decided to become recognized. It is still labeled as "Apple Wireless Mouse" in bluetooth devices though, but the proper preference pane appears now, and scrolling and tapping work.

Well, after installing the latest FakeSMC.kext rev391, and rebooting a couple of times after clearing out all caches with Onyx, 10.6.4 now recognizes my BT MagicMouse and allows one finger scrolling, two finger swiping, but freezes for about 20 secs if I try to use three finger tapping with MagicPrefs.

Any ideas (I've removed USBOverdrive and all associated ketxts).