Setting up Persistent Filenames is a two step process that has an important prerequisite: You must identify those elements that indicate the start of a Web chunk (individual page).
The easiest way is to make sure that those elements, which will signal the start of a new Web chunk, have an @id attribute with a valid value and then use that value as the resulting filename. It makes it both easy to track down and correct in the source file.
Once in place, it’s a matter of setting up a property set and making sure that property set is assigned to those same element rules.
For example, here’s how to set up a propertyset called “a_persistent_filename” that we use in the Arbortext Monster Garage books to create good web output and epub formats:

And here’s all the rules it got set on:
