I dont know the operators involved, however some operators have an exemption under CAR 152 for "Authorisation for parachute descents through cloud". I have also seen an NPRM that CASA has put forward to allow it.
Dont think the exemption actually covers the aircraft.
CASA has also issued Authorisation CASA 205/98 to the Australian Parachute Federation for "Authorisation and specification in relation to parachute descents".
CASA has also issued Authorisation CASA 206/98 to the Australian Sky Diving Association for "Authorisation and specification relating to parachute descents".