Lion midi signal

Dear friends,

I get the following problem with MIDI signals on Lion. I tried making midi work with 4 different software and 4 different hardware, the problem is definetely mac os x lion.

When I do a clean install of lion ( pure lion , no SL ) I don't get midi signals.

On the other hand, midi signals work fine on SL AND on Lion, if installed above SL !!!!

I really do need a clean install of Lion, because of the much much better performance...

Ideas ??

Thank you