literature Regarding Importing:

Here is a little bit of Lit on CURRENT laws for importation of "Soft Air" -BB guns.

Taken from http://www.customs.gov.au/site/page4369.asp#e1057
"Firearms and ammunition (restricted import)"

IMPORTING CATEGORY A AND B
FIREARMS
To import a firearm listed below (commonly referred to as
category A and B firearms under State and Territory legislation)
into Australia, importers must first obtain the written authorisation
of the police firearms or weapons registry in their State or
Territory or the Commonwealth Attorney-General’s Department.
Police Authorisation
This authorisation will be in the form of a B709A Importation of
Firearms – Police Confirmation and Certification Form (B709A
Form).
Category A and B firearms include:
• air rifle or soft air rifle
• rimfire rifle (other than a self-loading rimfire rifle)
• single-shot or double-barrel shotgun
• muzzle-loading firearm
• single-shot or double-barrel centre fire rifle
• repeating action centre fire rifle
• break-action shotgun/rifle combination
• l ever action or repeating bolt action shotgun.
Please note
The above information does not apply to category A and B
firearms with the following characteristics:
• i s substantially the same in appearance as a fully automatic
firearm
• i s fitted, whether by original design or by modification, with a
folding or detachable stock and capable of being fired when
the stock is in the folded position or removed.
To import category A and B firearms with these characteristics,
written permission must be obtained from the Commonwealth
Attorney-General’s Department.
Attorney-General’s Permission
Written permission to import must be obtained from the
Commonwealth Attorney-General’s Department where the
importation of category A and B firearms is for one of the
following purposes:
• government use (official purposes)
• for repair, modification, testing, training, government contract
or certain other project or tender, or for use in the production
of a film, for transhipment or for use by a foreign defence
force in a defence-sanctioned activity (specified purposes)
• for use by professional rural pest controllers (specified
person)
• the importer is a proven researcher or developer of firearms
or related defence and law enforcement products and the
article is being imported for the completion of a project or
tender
• previously exported firearms returning to Australia (returned
goods).
The original permission must be presented to Customs and
Border Protection at or before importation.


AMMUNITION
Ammunition for use with category A and B firearms also requires
an authorisation to be imported. When being imported with these
firearms, this ammunition can be listed on the same B709 Form
or Commonwealth Attorney-General’s permission as the firearms.


In a Nutshell, if you plan to import on of your beauty's. It must not Emulate a military style rifle, and MUST get either WRITTEN permission from Your states Police (EX. Signing of the Specific Forms) OR Written permission from The Attorney General.
Try your best with the police, I honestly doubt the Attorney-General is going to side with you.

FYI: It is too MY belief That this only Applies to Spring Snipers and Gas/Spring Pistols. While AEG's are off the Market, You can perhaps become world renowned Airsoft Snipers!
Best of luck ^^.