well I've found the solution to sync the arp / seq to midi clock with this : 3.3 MIDI Clock Settings Global PGM 1 = Respect Start/Stop (lit) Ignore Start/Stop (unlit)
But there's a new problem, the Messenger is not always "in time" with the other gear : you have to be very precise when starting the ...
my Messenger doesn't sync its arp nor sequencer with the tempo of my drum machine.
The other gear (Prophet 6, UBxA) midied to the Tr8s sync very well, however I've tried different midi settings with my Messenger. Did I miss something ?