I haven't tried this but i think it will work
What you need:
Block of wood
drill
a clamp
Drill a hole in the block of wood just big enough for your lock to go though then when the lock is inserted use any kind of clamp (like these http://www.htpaa.org.au/oztools-images/ ... arison.jpg ) and attach the clamp to the end where the locking mechanism is. I don't know if this will work since i have only picked locks in doors and don't have a spare lock floating around.