This is what I did:
http://personal.marionette.ca/Gregor%20%26%20Janice/Blog/851AE0C2-9B8A-4BC8-9CB3-54986A73867C.html
  part way down the page.   Just a big hasp and a padlock.

Gregor

On Wed, Jan 28, 2009 at 7:05 PM, Matthew Snook <matt@snooksband.com> wrote:
> Has anybody designed a securable storage method for Westies?  I travel with
> a couple of instruments, a laptop for work and sometimes some camera gear
> that I leave in the rig.  Everywhere you go are signs "don't leave valuables
> in the car," but if I'm going to hike or play on the beach, or attend
> meetings, that means that all my stuff is in the rig.  Locking the doors
> just doesn't slow thieves down enough. I want something that only a thief
> with chop-shop tools could break.  Or at least something so that if they
> break the windows, they don't automatically get all the contents of the car.
> Insurance will always pay, but that's not the point.
>
> I noticed that when I pull the rear seat forward into a bed, there is a
> space under the seat on the cabin side.  I started thinking that there might
> be a way to have a fold-down board or something with a lock on it to enclose
> that space and secure it for items I really don't want to lose.  Then when I
> get back I can take the stuff out, fold it out of the way as the seat goes
> back into place and I won't lose any valuable cabin space.  Any engineers
> out there?
>
> Matt
> '84 Westy
>
>