There seems to be some bug issues with the looper block at the moment in the latest firmware (according to some users). However:
Yes it is possible. You don´t really need to connect an momentary switch if you want to get really quick stutter. Any modifier will do. LFO or sequencer, perhaps (Run) triggered via envelope to match it to your playing...
Pretty simple actually. You've got the "buttons" on first page, on second page some of them are duplicated. The symbol next to them shows you that they could be assigned an modifier. Go to one of them and (double?)hit enter and chose your modifier controller...hey thanks for the reply. oh there is a bug? hm i would like to also know how to use modifiers with the looper?'didn't know you could do thatcould u explain how to :change the play button to momentary switch, and how to use modifiers on this thing ? thanks not sure how it works