I'm in Western Australia and I've been using the BX4 flatrate boxes for anything that fits because it's cheaper when posted to the Eastern States.  I set the postage to Flat at a cost of $17.45 ($15.05 for postage and $2.40 for the box).  I just had a buyer from WA contact me asking if I did pickup and that got me thinking.  I entered the box dimensions into the Australia Post Postage Calculator for postage within WA and it gave me a price of $8.95.  I'd like to add both the Flatrate Boxes AND Calculated Postage but nothing in the list looks like the BX4 boxes and if I click 'offer additional service' it just lets me include another Flatrate postage which really isn't helpful.  Am I missing something or is this an actual limitation within eBay?  I was going to complain about not being able to have an aditional charge for packaging, but I supposed you have to include that in the item price.

(PS. I added Pick-up)