Martin,
I've just studied real estate acquisition and the FIRB at uni, so I might have an answer.
Basically, unless the property you acquire is a new development, or vacant, urban-zoned land to be used for the construction of a new development; purchasing exisiting property is near impossible. There is really only one situation for gaining approval: if you gain a temporary residence visa and have at least 12 months from the time of application, you can enter into a contract of sale for a property ONLY if the property is to be used as your primary residence. Then, when your visa expires the property must be sold. You cannot continute to own the property and gain financial benefits from such an investment.
Basically, the FIRB's argument is that foreigners investing in existing property decrease the supply of housing for we Australians, thus increasing demand and placing strains on our economy and increasing domestic house prices.
The only real way around it is to marry an Australian and THEN think about it! Or, get a job, get sponsored, live here for 10 years and get naturalised. It'd be the best decision you ever made!
Hope this helps.