I haved mine for 2 months now and useing the cheezy dash vent mount.......
last night i was on the crutchfield sight and found that they carry a metal bracket mount thats made just for the Liberty.
it has a tab that mounts w/3 self taping screws behind the center stack and sticks out between the trim and the dash.
PN:042JP7302 Pro.Fit JP-73-02 Jeep Liberty 02-Up.......$35.99 w/free shiping.
it said that it is made to mount to the right of the heat/AC controls.
sorry i dont have any pic yet. hopefully it will be here sometime this week. They have a pic of it installed in a Liberty on the website.
Skymech
http://www.crutchfield.com/S-817sKGdmMDM/cgi-bin/ProdView.asp?g=251850&id=essential_info&i=042JP7302#Tab