Originally Posted by irmster
With the IST sales office now closed, does this mean I have to book through the Bremen call centre?
You can "book" with basically any OW office/desk..(BA/AA RTW among others, just like booking any other ticket...) Once you have a valid ITN you can contact the "ticketing" point in your country of origin, which in your case seems to be the call center you mentioned.
Please post your experiences with Bremen / IST pick-up. No information yet how it goes now after IST was closed...