I cut a scrap of sheet metal (I think from an old PC power supply) to be my mounting plate, and screwed it to the dash. Then I temporarily installed the bezel, marked the center of the factory switch plate opening onto this plate, removed both, drilled the switch holes, then installed the switch. It has some give, but it's plenty strong enough.

It's POSSIBLE that this switch is equivalent, but I haven't confirmed that:
{-Clickit

Owner caption September 2011 · Photo 175 of 401