Roof rack sliding mechanism broke...Help!

[landmark]

The button that you push to move the location of the roof rack broke out yesterday. The button itself has 1 small plastic tab on the top and 2 plastic tabs on the bottom. The tab on the top was the one that broke off. Does anybody know if I can take the rail clamp apart and just replace the button, or do I need to buy a whole new rail clamp?
http://home.att.net/~mark.kohler/pics/roofrail.jpg
By the way, I swiped the pic from a different thread. My roof rack is still attached to the jeep

Thanks for the help.

[lapisxj]

I just left the buttons off. You can take a pair of needle nose pliers or a flat tipped screwdriver and unlatch the rack bars. With the button missing you will see a vertical metal rod in the latch mechanism, you will want to grab that and push up till the latch unseats from the hole in the rack rail. Then you can slide to whatever position you want.