I don't think that you even need zak space.  Try something like this:

	instr 	1

kctl	init		1
kswitch	midictrl	1
		if			kswitch != 1 goto skip
kctl	midictrl	2

skip:
;	do your stuff

	endin

	Here, kctl will only be updated to a new value if controller 1 = 1. 
Otherwise, the old value will stay put.  The init makes sure that the value is
something if the note is initialized and controller 2 != 1.
-- 
Mike Berry
mikeb@nmol.com
http://www.nmol.com/users/mikeb