Rock Band Fender Mustang Pro-Guitar Rock Band 3 - Manual (Page 10)

A
CCELEROMETER
Rotational motion of the guitar can activate certain MIDI functions. To toggle these
functions, the correct button combination must be pressed.
Accelerometer MIDI Mapping
Axis Output Toggle Key
Combination MIDI Assignment
X Buttons 5 and 12 Modulation
Y Buttons 5 and 11 Expression
Z Buttons 5 and 9 Pitch Bend