Aust Post shipping by letter?

The Australia Post Shipping option only seems to calculate for parcels. As it is possible to ship small items as letters, is there some way to have this module deal with letter rates?

Hi Nicolas

I tried this but could not work out how to add letter rates for both Domestic and for International customers. There isn't any way to stop a domestic customer from seeing the international rate as an option. This gets a little confusing.

What I need is to setup one set of letter rates for Australia, and another set for all other countries. I can setup the set for Australia only, but there is no way to create a set of rates for all other countries without duplicating them for every country. If I don't select any zone at all for the international rates then the international rate is shown as an option for Australia.

Is there any documentation on how this could be done?

Thanks Nicholas. That seems to have solved the problem. Your help is greatly appreciated.