Actually, the Cert of Validation is only required if you wish to receive training (eg get a rating using a VH reg a/c). It is specifically tailored to the type of operation required (eg ferrying). It only lasts for 3 months, but can be renewed. Your o/s medical must be valid for this period. IFR can be flown.
Other than that, a special licence is all that is required, but may only be used for private day VFR ops. (You can get endos on a SPECPL.)
Make sure your English language cert is listed on your licence. If issued by a private agency (an all you have is their certificate) it won't be recognised.
Read Form 213 from Flight Crew Licencing Forms on the CASA website
http://www.casa.gov.au/wcmswr/_asset...cl/form213.pdf
Have fun!
