Simply booked the flights on aa.com, after everything was confirmed I gave AA reservations a call and asked them to tag the BAEC numbers to the booking, gave them the numbers and it was all done within a few minutes.

Having flown AA Domestic before (although not in First Class) I do laugh about how they print "EMERALD" in huge text across the boarding pass for BA Gold members. A bit over the top, but amusing none the less