Well the law says:
"(1) Subject to paragraph (2), a visitor who holds-
(a) a valid international driving permit; or
(b) a valid domestic driving permit or domestic driving licence,
issued in a place outside Hong Kong may drive in Hong Kong, during the period of 12 months following the date of his last entry into Hong Kong, a motor vehicle of any class which he is authorized by that permit or licence to drive notwithstanding that he is not a holder of a driving licence issued under these regulations, but so long as he has attained the age specified in regulation 7 for the issue of such driving licence in respect of the class of motor vehicle.
(2) Paragraph (1) shall not authorize a person to drive a motor vehicle of any class if he is disqualified from holding or obtaining a driving licence to drive a motor vehicle of that class."
and
""visitor" means any person who arrives in Hong Kong other than to take up residence for a period exceeding 12 months;"
So it seems pretty hard to see what exactly you would be charged with, never mind suffer jail time for, if you are driving on your overseas driving licence within the first 12 months of arriving in Hong Kong.