I don't think I've ever seen anythin quite like this ...
title Use a qwerty keyboard with GRUB
But anyway, if you are booted up into MEPIS, you can mount the FC3 system so you can have a look in it's /boot directory to see what it has for a kernel and initrd. Also, if your lucky there may be a menu.lst to look at. Then you can put that info into your MEPIS grub.
mount /dev/hdb3 /mnt/test