Alan,
Yes, the manual goes into the subject. Look for the "Midi" section of the manual. All you need to do is enter the Midi Menu pressing F6. On the top left of the screen there are the Channel Transmit and Channel Receive menus. All you need to do is to match the receive channels ["right" and "left"] of your X4, to your transmit channels on the midi controller.
Make sure the controller is transmiting the left and the right parts in DIFFERENT channels, otherwise you won't get the auto accompaniement!
Hope this helps,
-- José.
[This message has been edited by matias (edited 11-03-2002).]