Roland often obscured certain aspects of the MIDI implementation in Sysex manuals or Appendices etc. Current Roland website only offers the main manual, but it might not hurt to ask around and see if anything else came out back then that’s not available now.

There’s quite a lot of the basic OS panel functions that MIDI cannot address. Things like Perf Up/Down, Rit/Accel, 1/2 bar Fill, etc. etc.. And you simply have to find out for yourself which ones if you don’t have the full MIDI documentation…