Refit question: Adding os's manually

Hello, I am trying to tripleboot(mac/xp/debian) my macbook (2.4ghz/4gb/250gb).

Unfortunatly, this isn't really working. During the installation I can't seem to successfully install GRUB or LILO on the linux partition (/dev/sda4) (I would install it on the MBR, but I am not messing up my mac os!).

Is there anyway to manually specify a bootable partition (/vmlinuz on /dev/sda4) for use in refit?

Thanks!