Hi everybody,
I'm flying TLV-DFW in a few months and trying to puchase CW ticket, then trying to upgrade one of LHR-DFW, or DFW-LHR to F with miles.

The LHR-DFW segment is operated by AA, which has worse business class, and therefore decided to upgrade it.

Anyway, when trying to do the booking via the tool online (that does both booking and upgrading) I face a weird situation - for whatever segment that I decide to upgrade, the TLV-LHR portion (or return) changes to world traveller (although I selected club as the cabin, although there are available seats and although the LHR-DFW (or return) shows as F).

I also see availability for upgrading on the AA flights.

My question is as following - if I purchase the ticket (entirely in CW), and then try to upgrade - will this work for me? Will this work even though the AA flight will have BA code?
Or should I contact a TA to do this for me?

Thanks.