you want to get the wires out of the sheilding so VERY VERY CAREFULLY take some scissors and cut just enough off (not the whole thing just the sheathing.)
Undo the foil wrap if any (some connectors have this some dont)
Next strip off a little bit of the wires to the point of where you can still tell the color of the casing and have wire to solder to.
Ok, now that we have that prepped and ready to go onto the next step
Take your USB Extension Cable, and cut it directly in half
do the same thing with the USB cable as you did with the Xbox Breakaway
Cut away some of the sheathing, then get those wires out and stripped so you can solder to them,
and still see the color of the wire.
Next comes the fun part match up the wires in color and solder them together
(this is where i told you to have extra wire because it allows you to have more space to work with instead of holding the wires together.
Once you have soldered all the wires that match you will be left with a Yellow wire from the xbox breakaway
Well my friend you dont do anything with it, just leave it
Now my reccomendation is that once you make a nice solid solder connection use some electrical tape and cover it up so that there is no bare wire exposed
Allright! Huzzah! and whatever else you might want to say that makes you happy.
You now have the cable you wanted for whatever reason whether its to Play Grand theft auto 3 on your PC with your Xbox Controller S that you love so dearly
or to plug in a keyboard to your XBOX and actually TYPE on xbox Linux
Congrats! and Enjoy!