Is the 'Custom Preview File' another name for the sample book file referred to in Chapter 5 Preparing and Delivering Multi-Touch Books page 32.
referred to as the 'Publication Preview' in the Assets pane and 'Preview' in iTunes Connect.
I downloaded both files to iTunes connect resolved an issue in both files downloaded them again and I am now being asked to provide a Custom Preview File. I give up whats a Custom Preview File?
Retrieving data ...