Yep, I just bought a custom template myself and the seller had already modified to be used with Auctiva upon my request.
I did have to make some changes were easy to do with some playing with it (make sure you have it saved somewhere else first
)
I went to the listings tab and under create a custom template, I copied and pasted the hltml the seller gave me for the template. Then I switched to the Design Editor which lets you see the template as others see it. Here you add the Description tag and the image tags wherever you want these placed. THen you can click on save and preview to see how it looks. It does take some tinkering but I like the Design Editor so that I am NOT tinkering too much with html.
Hope that helps, if not, let us know and maybe I can look it at for you to see where the tags need to go.
Marcia