hi mike, got the same drama with mine, fitted a diff from a VN, cut down to size. question is what handbrake lever are you using? im using the original handbrake lever with the commodore rear cable and getting a cable made up from these guys to mate the two up.
http://www.autocables.com.au/ all you got to do is measure the distance between the two. i think i was quoted around $90.00
the other option is to use the commodore lever mounted between the seats, i was working on mine yesterday and im pretty sure the cable will reach to between the seats. SGO has done a setup using the centre mounted lever, try checking with him.
hope this is some help.
dean