I would recommend the latest Oz one (v1.6.2), it is much more stable than the nzTiVo one (v1.5). The only modification needed is to replace the timezone file afterwards for the latest daylight savings dates. The NZ emulator is an option on the image boot CD menus. Make sure you change the port to 8000 though.
http://forums.oztivo.net/showthread....t=Auckland.zip