Lock mounting for zippered security bag

In a zippered flexible walled security container having an elongated access opening, a lock housing disposed within the opening adjacent one end thereof, a slide fastener for closing said opening and including a lacing element movable along the opening between an open position wherein it is remote from the lock housing and a closed position wherein it is in close proximity to the lock housing and, in combination with the latter, closes the opening, a lock cylinder mounted for rotation in said housing, a keeper plate secured to the lock cylinder and projecting radially outwardly therefrom and adapted to overlie said lacing element and retain it in closed position, said lock housing having bores extending therethrough, apertures in said container adjacent one end and the access opening thereof, eyelet means affixed in said apertures, backing washer means associated with said eyelet means, and rivet means applied through said apertures and bores to mount said lock housing in said container whereby said backing washer means precludes button holing and disengagement of said rivet means and lock housing and back feeding of said slide fastener.