Emu XL-7 & MP-7 User's Group

Addendum # 1: If you want a button to simulate rotating the big data 
knob, try the following:

Increase value at cursor by 1 (+1):
F0 18 0F 00 55 40 22 01 00 01 00 F7

Decrease value at cursor by 1 (-1):
F0 18 0F 00 55 40 22 01 00 7F 7F F7 

So, if you are in the Song Mode View
and the transport is stopped 
and the cursor is under the song number (eg, 020^00) 
to select the next song, press a button to send +1.