How do i get an Insteon KeyPadLinc message from a button press?

I have been implementing insteon-MQTT (I-M) in HA as I replace an existing Mac Indigo Insteon installation. I’ve managed to get most everything working, with the exception of the KeyPadLinc, where I’m almost ready to give up.

I’m able to send a message TO the KPL and control the button LEDs, but I can’t get a message FROM the KPL. I’ve been able to use I-M to define scenes and pressing a button executes the scene, but there is no message from the KPL.

I am absolutely stuck, and could definitely use a hint or pointer to be able to transmit a message FROM the KPL to the modem that insteon-MQTT can hear.