Strange midi issue between keyboard and lil' mpc

Hi,

I have a problem with my midi keyboard (CME Ukey) and my MPC500.
I can't trigger samples via the keyboard.

I've set midi channel, connections are OK...
The strange thing is that I can trigger samples via another keyboard like the microkorg.
And I can control the microkorg with the CME Ukey.

So it's seems to be strictly related to the Ukey and the MPC together.
Any idea of what it could be ?

Are there special midi settings for the MPC ?

I tried this midi chain :

Ukey > Microkorg > Mpc500

And I actually can control the mpc500 with the Ukey now !
I guess the microkorg is filtering some data since it doesnt receive and transmit bank & program changes.

But that sucks, it means I can't use the MPC to sequence the microkorg...

Any ideas to fix this ?