30% vendor finance on positive geared property?

Could anyone help me please.
My sister is trying to sell her positively geared property in Daylesford. Her problem has been that the property is in the higher price bracket and even though it is magnificient with excellent financials it is out of most peoples price range. I have suggested to her that to make it easy for potential investors she consider offering 30% vendor finance at lower than bank interest rates so they do not have to come up with a deposit. (providing the investor gets 70% finance it is a nothing down deal not including costs and duties). She loves the idea and I ran the figures and the property is still positively geared at 100% finance.

Now I am stuck because I have no idea how you actually go about providing vendor finance. I assume in an instance like this you would hold a second mortgage over the property. Can anyone advise me where I can find some information. I was thinking of Steves Wrap Kit but this will not be a wrap just 30% vendor finance. [confused2][biggrin]