I doubt that CASA will allow you a basic instructor rating, but good luck. Even with current CASA check and training approvals on a whole varied fleet of GA fixed wing types such as C441, DC3, F27 etc I was unable to get a Grade 3 rating when I enquired a few years ago. Presumably because there is a world of difference teaching or testing a pilot who is already at least at CPL/IR level a few advanced 'tricks' compared with getting an ab initio ready for their first solo.