shortskoolbus, you should keep the original boarding pass before the mileage is credited to your Asia Miles account. If for some reason, your account still does not show the mileage, you will be required to send CX the boarding pass and e-ticket receipt to get the missing mileage.

If you do not have the boarding pass, I am afraid you can only credit the mileage to AA account. AA does not require the boaring pass for the flight of its own.