Yen-
I have the manuals for 91, 92, 93, & 94. I would bet the 91 manual would be fine for your '90. It's big, it's heavy and it would be expensive to ship to AU, but it covers absolutely everything on your car. To better describe the manual and it's contents, check out eBay auction #230313230949. It's already ended, but it gives a great description for these manuals.
If you are interested in one, email me off forum (cougar1prod@comcast.net), and we'll work out details!
--Russ