Kool stops *Continental , is fixed with a stud like that.. molded in.
http://www.koolstop.com/english/continental.html
the brake arm slot, of your (Unstated brakes) may be too narrow for the fancier ones,
buying online, thats* a guaranteed fit. they are long lasting..
I used mine a couple wet years , barely worn , any, when I sold the Bike.
there used to be a Matthauser brake pad using that exact pad holder..
Nut Fixed, bolt out the back..