Another useful technique with the ARP is to record its output as a MIDI Region first. Do that by connecting a cable from the ARP object to a Sequencer Input object (en the environment). The go to the arrange windwo and select the (instrument) track where you want to record the arpeggio. Oh... you have to first record the source pads on the ARP track to drive the ARP. The good points in this technique is that you get a chance to edit the arpeggio; like muting certain notes or groove quantizing it to play smoothly with rest of the parts.