Here's what I did.
http://www.montanaowners.com/forums/...11#post1117411
You could adapt it to your external system for the time by adding an extension cord from what I call the inverter ATS and run it to your external inverter using the 2-pole 30A breaker. That would prevent the inverter from powering bus on the primary breaker panel with the ACs and only the ones on the secondary with the general purpose receptacles/plugs.