ND B407 for MSFS 2020

Most Acars systems require a parking brake in order to start & end a flight log.

The B407 doesn’t have a parking brake therefore I cannot log flight with it as the Acars system we are using requires a parking brake toggle.

I tried editing the systems.cfg as follows:
parking_brake =1

However there still is no parking brake. How can I add a parking brake toggle to this aircraft so that I can log flights with it using various Acars systems?

Thanks in advance,