I tried installing any of the 3 bootloaders, but after reboot, I always get the Windows boot menu, and selecting "Mac OS X System" (with fast F8).
then I get "Darwin/x86 boot v5.0.132", and a menu of partitions. I select to boot my OSX partition. After few seconds, I see a white screen with an "apple" sign in the middle. few seconds later the machine reboots.

if instead I give a "-s" boot option, I see a lot of drives load up, with Mac paths (e.g. /System/Library/Extensions/ xxx)

After few seconds of loading many things (its runs extra-fast, so I can't really tell specific drivers), the screen clears, and I see about 10-20 lines in smaller font, and less than a second later, the machine reboots.

my understanding, is that it really starts to load the OSX, but then there is some problem with some driver, and it crashes -
do you think Chameleon would get me better? anyway, LG bios doesn't have any "bootloader" option.

the problem is that I don't have any boot.log, to understand where it failed. I don't know what boot options will force it to create a log.
scanning the OSX drive after such crash, I see that the install.log is the last file written - nothing is written during the boot sequence.

BTW - the XP is the original LG-created partition. my harddisk has the LG install partition, my XP partition, a backup partition, iACKTOS partition and OSX (iACTOS and backup are logical, all other are primary partitions)