Diki, I just read again the G1000's manual, and there is only 2 buttons for the chords sequencer.
One called REC/STOP and one called PLAY/STOP
I will do the same.

TedS, About the retriggering on Roland styles, I have found a solution, but I can't tell much about it...

I am now working on the BK-7m styles. They are playing quite good with vArranger and any sound module. I really like them !