I just figured this part out. You click on the Select Template (like you normally would to add an Auctiva template). Then, you select Custom from the drop down menu. After that, I found my custom template - although without a thumbnail.
Now, I'm having a different problem. When I preview my listing it shows my html, custom template as a background ONLY with a boxed in white, plain background with all my auction info in it. I want my entire background to be the template - not a white box inside my custom, background template.
Do I just do <background=...> or should I stick with <body background...>?
Thanks!