If you look at the switch from above there is a small hole to the side. Push a small screwdriver into the hole and lever the end of the blade towards the switch button whilst pulling up on the button, this releases the tang which holds the button in place. Be careful not to break the tang off. This will reveal a small torx screw which when removed will allow you to remove the switch assembly and replace the cable.
Leighton, October 2006