I'm currently trying to solve the same problem. I installed XP by ghosting the XP partition from anaother machine to my extended partition, but XP did not boot, because it needs to boot from a primary partition. I tried mapping partitions to make the XP boot loader see the partition as it was primary from the grub.conf, but it did not worked. map (hd0,0) (hd0,6) map (hd0,6) (hd0,0)