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).
Step 2: Two
Also you'll see that there are only two screws at the front of the pedal (under the ball of your foot) - I was going to put three per row but the two worked so well I have decided to leave things as they are.
If you were to trim them down I think the reflectors would fit back between the screws but as this is just my practice uni and not my main ride I did not bother to put them back.