during the last week i had a stubborn midi problem in audio units for apple mac 10.5
if someone have the same problem all you need to do (for getting midi events to your audio processor) is to change one line in the AU warrper.
so go to line 755 and instead of:
and, magic… you have midi
now a question,
do i need to duplicate the old function to have a 10.4 compatibility?
red_muze hope that this will solve your midi problem 8)