Thanks for posting your question here. The issue of the option to specify insurance as Required, Included, Optional, or Not Offers no longer being present on Auctiva's lister page for eBay AU listing page is a known problem that we expect to have corrected with our next site update, although I'm not quite sure when that will take place yet.
However, we should have all the eBay supported shipping services for eBay AU available for selection on our site.
There are not any shipping services called "small parcel" available for eBay AU (either within Auctiva or on the eBay "Sell your Item" form) but there are a couple different ones for prepaid 500 g satchels, such as AusPost Prepaid Express Post Satchel 500g, AusPost Prepaid Parcel Post Satchels 500g, and AusPost Registered Parcel Post Prepaid 500g Satchel.
If you need any further assistance with your account, please feel free to contact our customer support team by mousing over the "Help" tab within your account and selecting the "File Support Case" option.