Hi guys : Bob and rharv: I try to resume so I don't explain it again,
thank you for your help

That's the way I always did, remembering my old Technics KN3000, the sequencer provided almost 7 midi channels, but those options recording all at once like I did gave in PT the option to extract, and done very neat.
Now I use the NC2X as controller with also a MP113 Foot Bass controller.
So I can record an organ sound module, and the option to split the channels can be manage in the controller itself.
When I come to PT , got the split already prepare, that's when I so it as an issue, the fact of representing CH1-CH2, together after being make the Midi Channel extract.
In other words I had to redo what on Midi track 1 is given as CH1 again, thereafter, I can get the CH2 separately.