Airbus 225 Helo, Battery assignment

Any idea how to map the Master Battery to a Switch or Button whether it’s in the sim or Spad.next?
Nothing works so far.

Cheers.

Also, two out of three times, after following the checklist to star this beauty, I get this message on the MFD, AFCS Disengaged.
No way of getting it back, but also the MFD is not working.

Any ideas? Is this a bug?