Setup lilo into partition's superblock and load it from grub

I already have grub installed on MBR of harddisk. It's come from my ubuntu linux. Then I installing slackware and want to use slackware's lilo to load the slackware system. First, I install lilo into superblock of slackware's partition using this command:

lilo -b /dev/hda2

note:

Slackware partition is on hda2, maybe it is different with yours, depends on your system placed in harddisk (including position of disk controller and partition). In my case, I use PATA harddisk which set as primary on controller 0. And my slackware system is on second partition.

Second, edit grub's configuration file (menu.lst). Usually in /boot/grub/menu.lst. And then add this entry:
title Slackware Lilo
root (hd0,4) #for example, if your slackware partition in /dev/hda5
chainloader +1

Now, restart the system.

hope this helpful.