I've been going through this process for a while, trying to book a DONE5 ex-IST:

- Called BA RTW desk, the man who answered said they could not book a ticket to be issued by anyone except them at anything but the US price. He also said once booked they'd hold the ticket for 48 hours.

- Called 1st-air.net, they are probably a much easier option to get a ticket issued in IST, but it costs $600 more per ticket (see here).

- Called BA RTW desk again, this time a woman setup my ticket very quickly--I had all flights ready including flight numbers and had checked inventory on all--by just reading city code to city code, date, airline, flight number (in that strict order). Only thing she wouldn't do, is setup the first intercontinental segment on AA--I am flying IST-LHR-[european city]-LHR-LAX-...--and she would not book AA on LHR-LAX, although I am hoping I'll be able to change after issuing (since the rules only say no changes up to the first international segment which in my case would be IST-LHR). She even said that their pricing desk is backed up so she gave me a 40 day hold, I told her I would contact BA IST for pricing and ticketing.

- Called BA IST (IST number which routes to Bremen). I could barely understand the person who answered (both bad line and bad english), but he told me all RTW requests are handled by fax only and gave me the fax number (same one listed on BA.com for IST). Fax took quite a few attempts to send (it's also an IST number which routes to Bremen), and still waiting on a response from this fax.

I am afraid that Bremen will be less flexible than the IST office was and request payment by Turkish credit card, etc. I guess I'll have to wait and see. Otherwise, 1st-Air is still an option ($600 more expensive though, $550 each if 2 people), but the next best options for me are GIB/CDG/FRA (for $600-$800 more than IST) and I would really like to go to IST this year.

Does anyone think I will have a problem changing LHR-LAX from BA to AA? There are plenty other segments on BA (4 in Europe, 1 in Africa and 1 Africa-Europe) so I didn't think they would object, but they did.