you really should consider working with a soft sequencer. even the cheapest ones are more intuitive and flexible than an onboard seq. the pa50's seq. is ok, but is not an easy trip working with it.
why not try some free midi editors you can download from the internet. or go with cubase se (i think 99 usd) and that's already more than basic.
i use pa50 togheter with cubase sx2. you can do ALOT of editing.