From a quick read of the manual, it would
seem like you need to use channel 7. It
is normally used for gyro gain apparently
but is the only channel that appears to be switched when throwing the N/1/2 switch.

My hunch is that you'd have to mess w/ the gyro gain screen to get values that would
allow the GV1 to switch. I'd start w/ a
gain of 0, 50, 100 and then check the GV
test screen to see if it is switching as you
move through the modes.