Have you done your intial tests? I applied in March, sat my initial tests on Sep 24 (there were tests before then, but I wasn't in HK). Got a call a week later to say I passed the test, and had my first interview on Oct 8th (still considered as 'stage 1').
That was two weeks ago, I'm waiting to hear back to see if I get through to stage 2 (HR told me they will get back to me within 1 month - fingers crossed).
If you applied in May and your application is successful, they should have invited you to initial tests by now (I think they say if you don't hear back in 8 weeks then it's generally a 'no')...