Why not just install legacy grub
I just did one today like this:
(1) Using the Live CD installer at the last step click on Advanced and choose not to install grub
(2) When installation is done don't choose to restart, rather choose to keep using the Live CD.
(3) Since you just installed you should know the drive/partition # of your Karmic (or Lucid) so keep that in mind. If you have no idea the Boot Info Script should be helpful:
(4) From the Live Desktop run:
sudo mount /dev/sdXY /mnt
(of course XY must represent your drive and partition #'s!)
sudo mount --bind /dev /mnt/dev && sudo mount --bind /proc /mnt/proc && sudo mount --bind /dev/pts /mnt/dev/pts && sudo cp /etc/resolv.conf /mnt/etc/resolv.conf && sudo chroot /mnt
You should notice that the command prompt changes from ubuntu@ubuntu$ to # which means you're now root in that OS. I like to be sure I am where I want to be with "cat /etc/issue" and "df -H".
And when you're done:
sudo umount /mnt/dev/pts && sudo umount /mnt/dev && sudo umount /mnt/proc && sudo umount /mnt