Using the cable assembly spec'ed by the OP, I used a sharp knife to remove the insulating jacket from about one inch of the cable in the middle and to also remove the insulation from the black and brown wires (again as spec'ed by the OP). A quick solder bridge and a little electrical tape and everything worked great. For those looking for the minimum additional length, consider these items from www.cyberguy.com

131-0598 A male to mini B male (eight inches)
plus
131-0934 A female to A female

or for an even shorter chain try
131-0589 USB ADAPTER AM/B MINI 5-PIN M