Aargh. Really doesn't do Mac as shipped. According to the instructions, Fn + Num should toggle the num pad. On mine, the num pad is on when plugged in. Pressing Caps Lock once will switch from Num Pad to TKL mode and turn on Caps Lock. Another press turns off Caps Lock. It stays in TKL mode. The only way I have found to switch back to Num Pad is to re-plug the keyboard. Anyone?
MagicSmokeUpdated the firmware. Now Fn + Num works properly. However, the Caps Lock will still turn off the Num Lock mode.
Edit: The "00" key now works, too. Makes me wonder how the previous firmware got out in the wild. It was massively buggy.