Note, my reading of the example at the bottom of the ATO page...

Note, my reading of the example at the bottom of the ATO page suggests that for options bought after "September 1985", the cost base is the exercise price of the rights.

That would mean that if you exercise 100,000 options in SSN on 1st July 2011:
- You do not pay CGT on the sale of these options
- The new start date for the 12-month CGT discount period is the 1st of July 2011
- The cost-base for the new shares is 1.5c x 100,000 = $1500

So if you later sell those same options a year later (1st July 2012) for $100,000 you would be liable for 50% of your marginal tax rate over ($100,000 - $1,500) = $98,500