I did the same thing, I made a bracket that mounted a micro switch so that the brake peddle when moved off rest turns on the brake lights. The port can be pluged with a standard pipe plug 1/4"or 3/8" I can't remember which.
I believe a VW brake switch can be used as a replacement for the orginal pressure switch. I am sure if you take your picture, or better yet the switch itself, down to the parts store there will be a part there that will work. It is only a pressure activated switch, nothing special.