Been there, done that. More fun than a barrel full of tangled slinkies ... removing the vinyl sheath is the easy part. Trim off the vinyl to where you want to get the medal sheath cut back to.
Method 1
Take a pair of diagonal cutters (aka wire cutters) and squeeze the cutters so that the blade on one side of the cutters starts spreading the metal sheath coil. \
Just go far enough to open about 1/16th of a gap.
Repeat on the next coil out towards the end.
this will give you a piece of the winding exposed by itself that you can hold with the corner edge of a pair of pliers or vice grips.
Next take a pair of pliers or channel locks and grab right next to the exposed wire and rotate it to unwind the coil while holding the exposed piece tightly. Work your way out to the end , moving the pliers on the exposed piece so there always right next to the coil part.
Method 2
Follows the first method, but instead of unwinding, you nip cut the gapped coil, then repeat the squeeze to expose part and nip again, until you end up with a pile of tiny "C"s
Method 3
Starting at the end, spread the first coil, clamp the housing at the point you want to cut it and unwind the sheathing enough to start gapping it out all the way along the sheathing, working the cable through the opened-up coil.
Pics of the last method are in the 4th post in this thread ...
http://buggymasters.com/forum/showthread.php?t=2773