It seems to me, and what electrical knowledge I have, it wouldn't be a matter of fitting it. It's how well you think you can rig electrical wires and switches. If you go to the site sponsor's section of these forums, there is a link to the Hoffman Group. They have custom billet buttons in three different sizes. To be honest, you sould be able to go to your local car store or walmart and pick up a few electrical switches and wire. Just run the wires from your locking mechanism to the button and hide the wires under the carpet.
My point is, that fitting the buttons shouldn't be a problem because there are vast ammounts of various button/switch sizes out there.
"I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones." - Albert Einstein