You might have more luck by checking the Japanese sites/marketplaces like Yahoo Auctions. They tend to have a LOT of second-hand RS stuff for sale there, including a lot of HK parts. Waiting and looking for the specific item you are searching for can
unfortunately take a while, but just stick at it and you'll eventually find what you need.
Once you have found what your looking for, you can then use services such as "JapanRabbit" to import them from Japan. Just make sure you add the note "FOR USE WITH AIRSOFT" in the description!!! As long as you aren't importing restricted parts (i.e. load-bearing RS parts, etc), and just sticking to furniture/accessories, you shouldn't have any real problems.