I just ticketed through BA in IST this morning, all by email and using my US credit card. The tickets will be waiting at their CTO; we're spending a couple of days as tourists in Istanbul anyway (mid April), so I figured it would give me an opportunity to drop into the office and thank them personally (I assume I can find a florist somewhere near them.) After phones and faxes and emails to Tal in Warsaw and Istanbul, and the utter aggro of going through the BA N. America RTW desk (where I made the res so IST could see the PNR) dealing with the BA people in Istanbul was a downright pleasure.
When I asked Tal in IST if they could issue xONExs, they said they represent American (uh, yeah...) and that if I had consumer ticketing business with AA I should contact TK, their codeshare partner ex-IST. Well, er...
When I set up our itinerary, I tried to make it somewhat BA-friendly, using BA as the first over-water carrier (IST-LHR-YVR so we could get AA mileage.) Also I made it 16 segs so that the "run screaming" scenario had a lower chance of occuring, esp. if they could have the machine print the tix rather than hand-writing them (don't know.) I knew we're going to be changing things around this spring anyway, so the change fee was already built into our assumptions.
Anyway, a distinctly positive experience with BA in Istanbul. Nice people, rapid service... no complaints.