Yes you can use AA even if your 1st segment is not AA. I start my RTW from CPT next month on BA. No problems, except that any issues related to routing, etc must be done by them, not the other OW carriers. The fax number is 817-931-8737. I fax'ed my itinerary on 29-Jan at 4pm EST and by 7pm there was an e-mail with all of the flights booked. The next day I went to the city ticket office in DC and the wrote up the ticket for pickup on 31-Jan, all before the big price increase.