I seriously doubt that AA Canada would be willing to ticket this, esp. as the OP has carefully avoided flying AA on either Pacific or Atlantic (so not much revenue for AA on this ticket). A Canadian TA is probably the best choice for a first RTW purchase, and some charge <$100. Alternatively CX in YVR will issue the ticket without charge (presuming that NRT-HKG is on CX, and if it isn't then it should be). Dealing with CX is pretty good, and you can start by calling the CX 800 number in the US. There is no need (or value) in going through the AA RTW desk for this kind of routing. Not sure how much higher CX taxes are than AA (but you would have to go to NRT by the ticketing deadline and pay for the ticket in person, if you want it to be AA issued, I think).