I can't help you with your particular licence, but things changed with the introduction of the JAA and now EASA.
I have an ICAO type 2 Aircraft Maintenance Engineers Licecence - CAD. When I first got this it was issued on the basis of my UK CAA LWTR, all I had to do was an exam on legislation. All type training was recognised both ways. After all the CAD was an annex of the UK CAA.
Now with EASA, unless any training is carried out by an EASA 147 approved training school they will not recognise it, even if it is to the industry standard ATA 104 level 3. I had to redo an A340 type course with an EASA approved school to get that type on my EASA licence. Even though I had previously done one with CX some 10 years prior. And the EASA approved course was a complete crock of ......
One day I could certify EASA registered a/c the next day I could not.
Until there is any cross recognition from EASA and HKG you just can't convert it. And the liklehood is it will never happen.