U can remove the region code using firmware upgrade, see this for more info...
http://www.artecusa.com/tech-support-firmware.html
But anyways, i have never tried it, and ask support from members/dealers before going on...
Hmm... after u unlock ur drive, u can install
DVD Region Free, It also supports region-locked (RPC-2) DVD drive, and does not require firmware modifications. It has no previous limitations and it will work, even if you can not change the DVD drive's region anymore.
http://www.dvdidle.com/dvd-region-free.htm