It needs to be issued in Hong Kong or in Canada, and needs to start from HKG. Without being there in person you can have it issued as an e-ticket by a travel agent or the Hong Kong AA agent as posted upthread.

You'd need positioning flights to get to HKG to start it, and from HKG after it ends, E.g., an LAX-HKG RT that has an outbound date before the DCIR22 starts, and an inbound date after it ends.

Normally, the fare paid is the more expensive of the fare where it starts and the fare where it is purchased, but there is an exception when purchasing in Canada. So, one option is to have the AA RTW desk set it up for purchase in Canada, then buy it at an airport somewhere in Canada where AA flies, or by a travel agent in Canada who can issue tickets from Sabre.