Check very carefully before doing anything.
I have a '93 Grand Cherokee and adding a hitch just doesn't do what the factory does. In the GC and other models, Jeep changed axle ratios, cooling and wiring BEFORE adding the hitch, the towing package is MUCH more than a hitch.
The Liberty adds a power steering cooler and heavy duty engine cooling along with wiring and a hitch, I'm not sure what else is done but Jeeps are much better off with the factory tow package.