There is an easy work around for addressing ports 7-12. Add a mrf350 as a device in your file. Your not actually installing a mrf350 your just using it to give you the ability to assign 6 more devices in the system. Re-label it something like msc ports 7-12. Set the rf ID's of the msc and the mrf350 to two different ID's. Then go into the mx980 and set assign all of your or settings and you will be good to go.

Been a long day, I can send you some more ideas for the rest of your posts tomorow.