also see this link:
http://law.ato.gov.au/atolaw/view.htm?locid='CGD/TD33/NAT/ATO'
4. In the past, where unidentifiable shares have been disposed of, the Commissioner has accepted 'first-in first-out' as a reasonable basis of identification. For CGT purposes, the Commissioner will also accept the taxpayer's selection of the identity of shares disposed of.
