A more official page on the e-cert on your smart id card : smartid.gov.hk - Using the e-Cert on a Smart ID Card, plus other interesting information on the smartcard at www.smartid.gov.hk/en/index.html.
Older blog entries:
http://kaykays.com/archives/000503.html#000503 (New HK smart ID cards)
http://kaykays.com/archives/000474.html#000474 (Update on HK's smart ID card)