The original post really puzzles me. I'm unsure how anyone can say the owner's manual is quite brief and doesn't go into depth. Every function is covered, albeit sometimes not as thoroughly as one might like (the ubiquitous Transmit Edit question), but generally everything's there.
Is this another question about the JV/XP manual that actually derives from a lack of understanding of MIDI or sequencing or editing or basic functions rather than from any shortcomings in the manual? Remember, the manual doesn't explain MIDI or editing parameters or general synth functions. It tells how to access those functions on the JV/XP.
Do you have specific questions?