in song mode set the seq you wanna repeat, and change the reps and then hit convert, it will make a new seq that will be for however many times you made it rep.
Example:
seq one (4 bars)
seq one (4bars) rep "2" and convert will give you a new seq that is 8 bars. (the same 4 bars but now loops twice to make 8 bars. hope this helps, im at work and not looking at my mp