Have booked international trips with them before, but have not run into this problem. I'm unable to obtain seat assignments on our United TATL flights even as a 1K - have called United, they can't access the seat map since it was booked as an Air Canada flight (I've done code-shares before, and haven't had this problem - we always fly UAL over the water so it is definitely a United flight), Air Canada also can not access the seat map, nor can Vayama (after several phone calls to all). The return is booked as Lufthansa, but again is a United TATL, can't get seat assignments for that one either. Ugh! Guess I won't be able to save hundreds by booking with Vayama anymore... it's just not worth not being able to get a secure acceptable seat assignment!