AU instruments won't read midi data!?

Hey,

I'm not sure if this is a new problem that came from an update or wether something that has always not worked as it's the first time I tried it but...

I just created a orchestral part in my notation software Sibelius then exported it as midi to open in Logic to get better sounds. Now in Logic the basic Logic and garageband instruments and play the midi parts fine, but as soon as I asign them to AU instruments via Kontact they just don't play. I can still record the AUs live at my midi keyboard but they just won't find the existing midi.

Can someone please tell me how stupid I am?

Also I have just set up my Sibelius to play through Logic for the beter sounds and it's the same story re not playing the AU instruments.