Surefire641 I don’t know if It works for you, bu you can try to send the 2 cc messages, first to activate the CC and the second one 0.3 seconds after to deactivate, something like this
Midi@00:00.10: CC54.127@1
Midi@00:00.40: CC54.0@1
I have the Yamaha MD-BT01 and a headrush and if I don’t send the second message it recognized as a press and hold.
Hope it works