So I've got the MTC generator working! With the excellent documentation I was even able to change the framerate from 30 to 25 fps which is necessary for perfect timing in Max.
Now I'm wondering if it would be possible to use the MTC generator in a M4L device (as Live doesn't support MTC output). But it seems that the frame messages are not passed through midiout of M4L devices. Do you think there is some workaround?