Meanwhile, you are posting here most likely on a computer that is MORE than capable of editing some MIDI files...

Why do you particularly want to do it on a piece of kit that is NOT designed to do it, rather than use what you already have? Editing MIDI files even on the built-in sequencers of most arrangers is FAR easier than any Palm software, and a computer, with it's comparatively HUGE display, it's a walk in the park...