No complicated tools needed - I did all by hand, no power tools used - just an old chuck to grip the drill bit and a good quality screw driver.
Step 1: One
Pop out the reflective strips that sat in the pedal body.
Find some wood or self tapping screws that will protrude about 1/8 (3mm) from the pedal after passing all the way through - but! only after you have filed off the very sharp pointed tips - file them down first - don't worry they will still happily screw into the plastic.
Drill a hole from one side to the other using a drill bit that is the size of the shaft of the screw (not the size of the thread or it will fall right through).