http://www.scopestuff.com/ss_b2ce.htm not in AU but great to deal with , with my D70 I used the t-ring to suit and got a Scopestuff adapter TA2P
http://www.scopestuff.com/ss_tadpt.htm to work with the orion 80ed {it has filter threads and i can hook up a meade focak reducer as well } also replaced the standard visual back that came with the orion 80ed {same one you pictured } with one from Scopestuff that uses compression rings
http://www.scopestuff.com/ss_fas2.htm