If I member correctly, the reflectors I had on an old set slide to the side and exit the reflector holder thru a slot on the side.
Is there an opening on one side of the reflector holding fixture?
Looking at an old set on ahybrid, there is an outside on the inside of the pedal where the reflector slides out.
Oops, meant outside
IMG_8883 by
gulpxtreme, on Flickr