Xbox Live Cards Region Specific?

I made the stupid mistake of setting my account to Hong Kong region, as I lived in China so I thought that I'd select the closest spot I could. After discovering LIVE offered little to no service there, I made another account purely for downloading DLC, demoes and the like, set to US region. Now that I'm moving to the US I want to get Gold membership, but paying by credit card means I have to pay in HKD, which means I have to pay the extra to change currency. So my question is can I buy the cards in the states or off Amazon for XBOX live gold or microsoft points and still have them used on my Hong Kong account?

the microsoft point card are region specific but the xbox live cards are rregion free (although i think the twelve month starter pack is region specific because it is bundled with 200 microsoft points)

not sure if this site is still up but it sheds a bit of light on the topic:

http://www.microsoftpointsxbox.com/

thanks guys.