You can see in this image how the cables are wrapped around the Reel Gear and how the cable ends fit into the holes. The Bottom of the set hole is marked so you will be able to tell which side should be bottom because it is rounded off. The rounding is to prevent stress damage and fraying to the cable when you wind and unwind it using the boots. So it's important that the cables be places properly in that respect.
So you can see how small the set screw is by comparison and probably why you should pick up some spares.
Replacing the pieces is EXTREMELY easy once you see how they come off for yourself and get over the fear of breaking the system
A quick view looking down as if you were wearing the boot. The 2 labled holes are where the cables are inserted. The bottom is inserted at that position after you have laced it. The top is inserted there after you have set it in the starting guide that rests at the bend of the boot and you are going to lace it up through the top guides and set it into the Front Reel.
To remove the front reel you need to pull all the slack out of the cable on both sides and then depress the Reel Wheel in order to hold it in place while you unscrew it. Now after you unscrew it, don't be surprised if the reel suddenly winds itself back up. Simply pull the cable all the way out again. Hold the cable like that while you losen the set screw for the opposite end of the cable.
AS you can see here there are 2 set screws that have to be losened and 2 viewing holes, 1 for each cable end. You should be able to see the end of the cable through the view hole after you insert it. IF you can't, you need to withdraw it and try again until you do.
WARNINGS! I decided to cheat and use a small screw driver to hold the reel in place while unscrewing the cables as it is spring loaded. DO NOT completely unscrew the set screw(s). If you leave them partially in, the housing is designed to use the set screws in that position to hold the spring loaded reel in place while you load the cable ends back in place.
However! If you do not have something suitable to hold it in place or you simple sneeze and it ends up winding up without the cables in place, don't worry or freak out! All you have to do is flip the Torque driver around and use the butt end like a screw driver(it's made for this purpose) to unwind the spring. It's not hard, but be sure that you do it until you cannot unwind it any further. Don't force it but gentle even force should not be enough to move it. Check the holes to see if they are aligned and then hold it in place with something until you can get the set screws back in place to hold it.