Oplab expansion port

Is there a way to go below middle C on the input ports on the expansion port? I’m in drum mode and I would like the first input port to trigger the kick drum but I can’t see how to do that. Transposing down doesn’t work, also tried different modes etc. So, I’m not sure if I need to implement some circuits between the piezoelectric sensor and the input port. I wish the Oplab came with a detailed project book kinda like the Littlebits synth kit.

TE got back to me, and it turns out that the input ports are hardwired to specific midi notes. That’s kinda lame. I really hope that gets changed in a future firmware update.