Volume of 2nd Keyboard

[Mikekeys]

Hi,

I have connected a 2nd keyboard to my PA1000 and MIDI bass pedals and an expression pedal to play like an organ setup.

The problem is the expression pedal controls the Pa1000 but not the 2nd keyboard.

Is there any way of programming this, or will i just have to either use a volume pedal or a dual expression pedal (Roland EV30).

Thanks