Do you have US Airways elite status? You can't book partner awards online and I believe they charge a bunch of fees to non-elites.

The US program is very, very primitive. Works out quite well for elites but it's definitely not a place I'd park miles without status. United would be a better place than US if you're chasing a Star Alliance award. (Aeroplan might as well, although I know little about it other than it allows for more generous routings than some other programs.)

US offers a modest bargain (vs. most other major carriers) if you're only going as far as North Asia. That could be worthwhile, offsetting the fees and hassle of talking to a human being to book the award. But for SE Asia, I don't believe that discount vs. United exists.