Under the CAR 31 licensing you need to an SOE for lower groups yes
Read the AAC's in relation to this
http://casa.gov.au/wcmswr/_assets/ma...ad/aac9-00.pdf
AAC 9-91 Issue 27 Administration and Procedure - AME Licences - Category Airframe
AAC 9-92 Issue 28 Administration and Procedure - AME Licences - Category Engines
AAC 9-93 Issue 18 Administration and Procedure - AME Licences - Category Radio
AAC 9-94 Issue 21 Administration and Procedure - AME Licences - Category Electrical
AAC 9-95 Issue 23 Administration and Procedure - AME Licences - Category Instruments
Required times are in the Category PDF's . SOE PDF'S are on the CASA website for free download