Originally Posted by
JALPak
No, the US site won't work in some cases because the JL flight won't show up even if you enter your JL PNR. It is the marketing carrier that's responsible for selecting a seat so OP needs to call AA or wait till AA OLCI opens which is T-24 instead of T-72.
In my experience, though, if you call AA they will give you the JAL reference and say call JL. They will not touch the seat assignment.