Well, I was pretty surprised when I saw that, but they don't have a freaking support!
Anyway, apparently, I must do that:
"The Keyboard must send the midi notes on channel 1, and being sure that the DAW is not changing this midi channel"
And in other words:
"You must send you'r external MIDI to you'r plugin from your own internal keyboard"
And I cannot make any plug in work when I change the midi channel output from "All" to "1" or "2" or anything else!