A valid tax invoice (on your company letterhead) which includes the name of your company and your ABN addressed to the Department of Business and Innovation. (PDF)
A valid invoice must include a description including the name of the recipient and the address, the name and date of the trade event and the grant category applied for.
Example: Grant for OFC 2012, 7-9 November 2012. Networker category. The invoice should specify grant amount claimed plus the GST amount with a total figure and should have the words 'Tax Invoice' prominently stated.