I also have this model and it took me a long time to find the solution. It turns out this model is actually an LG.
If you use the instructions for an lg-6000, it worked for me.
Here is a thread I found on another site:
I found a website (http://lgregionfree.tripod.com/) that has a different CD image for LG 6000 series players. I tried that and it works, my player is now set to region 0 and has played region 1, 2 and 4 discs.
Here is the process:
1) Download http://lgregionfree.tripod.com/6000.zip
2) Extract the ZIP file, which contains a Readme file and a directory named RMTM0000
3) Using a CD burning program, burn the RMTM0000 directory to a CDR, making sure to use the ISO9660 file system instead of the default Joliet. Finalize the disc.
3) Turn on the player and insert the disc. The Region Test Menu screen should appear.
4) On the remote, press your desired region (or 0 for regionfree), then press Enter then Pause.
5) Eject the CDR and turn the player off.
6) Turn the player back on and enjoy.
a) I did not need to wait a minute between region selection and pause.
b) On some players this hack causes the buttons on the player itself (not the remote) to stop working. I can confirm that on the XBV443 the player buttons continue to work.