Mate I looked into this less than a couple of weeks ago. I did the on-line assessment and got 160 points, you need 100 to be considered.
Then what happens is you receive an e-mail to confirm a time and date when a representative from the Australian Visa dept. can contact you and go into it further.
It turns out that you used to be able to go solely on experience, to be confirmed via references, and did not have to have any formal qualifications. This was suspended because people where getting anybody to write there references. Since this happened, people getting into Australia dropped dramatically!
I have the same problem as you, no formal qualifications, but 6 years experience. The very nice lady from the Visa dept. told me that they will be bringing this back in September this year, to encourage people back over there.
So if I was you I would take the assessment, speak to the nice Visa people and then speak again later in the year, saves all the hassle of exams!
Hope this helps


