From the HKG AIP
3.4 TRACK KEEPING ACCURACY
3.4.1 SID procedures are based on aircraft accurately following the published track as defined by the SID navigation aids, reporting points and waypoints. Pilots using FMS/RNAV equipment should note that in order to ensure terrain clearance, Hong Kong SID Significant Points/Waypoints PORPA, PRAWN and ROVER are 'flyover' locations. All other SID Reporting Points/Waypoints are ‘flyby’ locations and turn anticipation by the FMS/RNAV is permitted, however pilots shall comply with the published speed control procedures to limit the radius of turn,
unless otherwise advised by ATC.
http://www.hkatc.gov.hk/HK_AIP/AIP/ENR/HK_ENR1.5.pdf
From our HKG Port Page
CANCEL SPEED CONTROL: immediate acceleration is available at any point on the departure (subject to company SOP speed requirements) after ATC cancel speed control. ATC will already have calculated that the aircraft will remain within the departure terrain safety area with allowances for climb performance, wind and higher departure speed.
The AIP quote is pretty clear, but I'd suggest you get your company's flight ops department to formally contact HKG ATC if further clarification is needed. From a driver's point of view, ATC will apply radar terrain separation (rather than the procedural terrain separation provided by the SID) and "cancel speed control" when:
1) prior to the turn when you're already near or above the radar min alt and have a good rate of climb e.g. once you're above 4300ft, the 220kt restriction has no purpose; or
2) they see you're in the turn and nearly established on the outbound track anyway - again with no chance of extending out to the east and infringing on the radar min alt segments while below their height.