if you're in Ableton, just hit the config button on the synth at the button of the screen.. that should pop open your synth.. then click the arp on/off switch inside your synth.. then click whatever button on your controller.. that should enable that button to turn on/off the arpeggiator.. You could also assign (using the same method) a button on your controller to a delay.. Although, I'd set up a send and return channel for FX leaving your original content original, and using the FX as an add on.. Then you would automate the send instead of an actual synth parameter.. Keeps the original sound sounding pristine..