I don't know about the ASX, but directors have a statuory duty...

I don't know about the ASX, but directors have a statuory duty of care to the company and in situations like sale of assets of the company, may owe a fiduciary duty to the shareholders. The ASIC can sue the directors for breach of statutory duties.
In AOE's case, the directors did not say much except they recommended the sale. It may not be easy to establish whether they have breached their fiduciary duty or not. However, comparing that to the Sybase case, the AOE directors did seem to have rushed a bit into the deal and may have "adopted measures to expedite the completion of the deal, fend off rival bids and keep their jobs after the merger".