These ebuilds come from http://code.google.com/p/gentoo-china-overlay.
If you have some problems, go to the official site first.
west-chamber : xtables addons that may crash GFW, named after the Romance_of_the_West_Chamber ( http://code.google.com/p/scholarzhang/ )
Add an ebuild in portage :
The ebuild is now in the portage tree.
You can also use layman : emerge layman then layman -a gentoo-china
For Paludis use this rsync : rsync://gentoo.zugaina.org/gentoo-china-portage
If you have a problem : ycarus(-at-)zugaina.org