GRUB killing windows

[Azrael90]

2 drives
160 gig (Ubuntu)
200 gig (windows xp)
1 Raid for both of them

After installing Ubuntu I can only start Ubuntu. Windows is still on the drive but GRUB is not detecting it? Is this caused by the Raid controller ? How can I fix this ?

[VMC]

from within ubuntu. Open terminal and type 'sudo fdisk -l'. Write down the Windows /dev/sdx numbers

Then you can add to the last line to /boot/grub/menu.lst

Something looking like this:
title Windows
map (hd0) (hd1)
map (hd1) (hd0)
root (hd1,0)
chainloader +1