It should work, but if you can you should try to get BT as the 3rd OS. I just remember that was optimal when i installed OSX, XP and BT3 on my macbook.
I have been having problems installing BT on my brand-new mbpr, BT5R2 would not boot at all, but BT5R1 installs fine. Except that it forces me to have a swap partition, which i suspect is causing the MBR partition map error that refit is giving me after repeated clean wipes and multiple tries. What kind of results is the refit partition sync tool giving you? Im curious also, if BT5R2 is putting a swap file on your hdd as well?
Let me know how it goes.