TMTS,
I don't recall the particular CAO, but it used to be that a pilot with FAA ratings had to obtain 200 hrs commercial experience using that licence before one could return to Australia and convert to a CASA licence. I believe this was done to discourage people going over to the USA and getting a licence in a much shorter, and at the time cheaper, than in Australia (when our dollar was
worth alot more than today)
I had done the same as you are talking about and had only the Air Law exam and a check ride.
Contacting CASA would be your best bet.
Good Luck
M/V