It sounds like you have not created your Seller Details profile yet. You can create a Seller Details profile by clicking the Seller Details link under the Profiles tab within your Auctiva account. When creating your Seller Details, you have the option to enter information from any or all of the available sections and, when you use a particular Seller Details profile for your listings, only the sections for which you entered information will be displayed within the template.
To use your newly created Seller Details profile, select a template on the Auctiva lister page and then select a Seller Details profile from the Seller Details pull-down menu, which is located directly to the right on the Select Template button on the Auctiva lister page.
You should see the decorated tags for the different sections appear on your listings!
With customized template it is hard to tell if something is going to react oddly with eBay code or different browsers. Our preview will show you if there is gong to be horizontal scroll to a certain extent but it is not "live" so there are some limitations as to what problems you are going to see.
One thing to try is to create your listing and save it, then go the the Saved Listings page and get the HTML using the link on the right of the listing, take that HTML to here http://www.practiceboard.com/ and paste it in. You can do that in FF and IE to see if what you customized might have any problems.
And you are right, depending on how large your images are, pairing them can cause the horizontal scroll regardless of the code of the template.
Hope that helps!