You might considering a system similar to what the supercats use. Seems much easier to make at home. You would have to modify your jib some, but not much. You may be able to see some of it here.

Basically you made your bridles wires as you would in a non-NA rig. Use a SS rod goes below your forestay to a ring around the spin pole. A pair of cables locate that ring to either side using the bridle tangs.

http://www.thebeachcats.com/classifieds/catamarans-for-sale/p13103.html