Instructions for replacing the cables on most makes of garage door are available on the following page of the Amourelle Ltd website: www.amourelle.co.uk/instructions.htm
I hope this is of help,
Best Regards,
Nick Goldring
Amourelle Products Ltd - The Garage Door Spares & Automation Specialists - www.amourelle.co.uk
8 Ambleside Close, Woodley, Reading, Berks. RG5 4JJ - Registered in England No. 1640847
Nick Goldring - Amourelle Products Ltd, May 2010