I use the Overland A32x series all the time, and I have many airports with Aerosoft's AES installed. The problem is, that since I like all of the "eye candy" involved, it can take a while from engine shut-down until I'm ready for pushback. If I wait too long (we're talking maybe 5 minutes), then my aircraft systems shutdown. Similar to hitting Shift-M. However, I can't hit shift-M to turn everything back on. I either have to hit ctrl-E or select another aircraft. Is there anything like a ground power unit to keep my systems running for a little while at the gate? thx.

Well, no. If you have FSUIPC, though, you can extend the battery life of the aircraft a good amount of time. However, for that, you need to have FSUIPC registered, and it costs about 25 euros, I think...