[GadgetKen]

Chinaroam, welcome to Prepaidgsm.net!
A few suggestions (others may have other thoughts they can share)
1) See if you can buy just a local prepaid gsm sim card at a mobile phone shop. There are several carriers in Hong Kong:
GSM Coverage Maps | Hong Kong (China)
Once you establish the sim chip will work OK in your phone(see if the dealer will let you test the sim card in the shop), purchase enough refill vouchers to last your trip. Even if you have to throw the card away when you return home, at least this will give you immediate wireless communication. If you travel frequently to Hong Kong you might want to see if you can refill the sim card over the internet to keep the account alive for future trips.
2) Buy a prepaid landline calling card and use it at payphones (hotel room phones likely add high surcharges, so a payphone is better). It's low tech but it's a quick, reliable and inexpensive solution.
3) If you are traveling with a laptop, try calling back home with Skype or another VOIP provider. Do a test call first to see if the wifi connection you have access to gives acceptable voice quality.
4) When you get home, order a different callback sim card that has a decent price per minute for your travels but is also reliable (it's a balancing act, it's sometimes worth paying a bit more to get more reliable service). This website has several providers reviewed. Read through comments on the forums to make sure the vendor will work for you.