I'm just gonna give the fish instead of teaching to fish
because, to me, it should be thoroughly documented for the install and, as far as I could see, isn't. 2.6.7 should be an alternate choice in the initial setup instead of having to upgrade immediately post-install, anyway, and I didn't see that, either.
cp /lib/modules/2.6.7/kernel/fs/reiserfs/reiserfs.ko .
image = /boot/vmlinuz-generic-2.6.7
label = myLabel
root = myRoot
initrd = /boot/initrd.gz
If you need anything else, just copy anything else to the initrd-tree. Good luck.