For international Southwest flights (unlike AirTran), you can check in online at t-24 as usual and reserve a boarding position. You then get your actual boarding pass at the counter after passport verification. I suspect since they plan to move everything over to Southwest, the issue (one of many with travel on AirTran) will resolve itself. Although I agree that, at some point, they need to address seating on international flights. I also suspect that will include monetized reserved seating.