We are new to using Auctiva but since no one else has answered- no you do not have to use auctiva to list in order to have you showcase appear. If you are registered with Auctiva and have an Ebay token you can put your store window into your auctions using the HTML. Go to the store tab near the top of the page, then click on Store Window. Near the bottom there will be a link to your personalized HTML code for your store window. Copy and past that into your listing(make sure you are using the HTML view when you do). There are better directions for doing this when you find the HTML code.