I think that the Keylab doesn't behave the way it's descibed in the manual. The manual says (on page 24):
"Ctrl Toggle: set the min/max range, and then each time this control is activated it will transmit one value, then the other, etc."
However when I set a pad to Control Toggle it will show the correct behavior visually (switching the LED on and off each time I press it) but it still sends momentary pressure values to Gig Performer. That's what causes the problem apparently. Any way to fix this?
(EDIT: It even recognizes this behavior on the keyboard's display where it will show the last signal sent.)
The work around you suggested doesn't do the trick as it doesn't allow state changes.