Posting on japan forums - blocked?

Many forums seem to have blocked posts from IPs outside of japan, probably due to spam. I've lost the ability to post in one of my favorite forums as a result. Some of the forum software seems to be quite smart - I tried using a transparent proxy based in Japan, but somehow it still seems to recognize that I'm not in Japan.

Does anyone know any way around this?

Usually if you contact the admin for the site they can make an exemption for your account. I have come across the same problem with a Kansas City (MO) based BBQ site, but then I couldn't be bothered going through the motions and found a different site .
Which forum are you talking about if I may pry?