Pass CAD
I would suggest trying another regional flight surgeon or ask the institute directly for the test.
Alternatively take and pass an initial CAD class one medical, try DR O'Tremba at Vio and partners. CX are only interested in you passing the medical, ask them what further colour vision test would be done in HK.
Maybe go to UK and get the CAA test done. I'd be a bit wary of doing the FAA test in case you fail and lose that medical!