If I understand correctly you wish to earn AAmiles on the base economy fare, but use AsiaMiles to upgrade to Business.
You can earn AAdvantage points on fare basis Y, B, H.
To upgrade using AsiaMiles you need one of the fare bases YBHKLMS. This also being the bases on which you would earn AsiaMiles.
The cost of an upgrade SFO-HKG is 35,000 AsiaMiles one-way or 60,000 roundtrip. An award business class ticket would be 120,000 AsiaMiles.
You can transfer Starwood points 1:1 to AsiaMiles.