Thank you very much for your answer. That is a shame! I thought I could start the arp in the WXP1 from the Octatrack the same way I start the step sequencer if I gave it the Midi Clock. Something like:
I hit play on the Octatrack (Master, sends midi clock) ---> XWP1 Arp starts (slave receives midi clock).
I guess I will have to adapt and find a way, the thing is that even though they are clock synced, when you play the chord on the XWP1 that is going to be arpeggiated and at the same time you hit play on the Octatrack, they are a little bit out of sync. A different thing happens when you just hit play on one device and the other one receives the order to start at the same time without touching it, as happens with the WXP1 step sequencer.
Is it possible to create a phrase sequence in the XWP1 playing the arpeggio and then start the phrase sequence from the Master Device, in this case, the Octatrack? Could it be a workaround?