Some advice needed if possible. I'm trying to book BA & AA for the following return route:

FAO - LGW
LHR - MIA
MIA - NAS

I will be doing buiness in each of these places so all require at least one night layover, but I am not able to book the through oneworld. I can book the first 2 parts though BA online but because I have an address in Portugal I am unable to book with AA online. Neither BA or AA are able to help me out!!

Any advise would be appreciated
Thanks
Alex