John if you grab the current dpwnload of B-5 you will see there are added options in the CC assign page. There is now a toggle option to allow mapping of controller on/off buttons to, for example, percussion on/off.

MainStage 3 | Axiom 61 2nd Gen | Pianoteq | B5 | XK3c | EV ZLX 12P
Hoping everyone stays safe and well and sees this through to the other side