As I understand it this package is a website copier and html files are what
drive the website. Also all the links to the files you are insterested reside
on the html page.

At first I tried to do the same thing. I don't think it possible. And you
wouldnt have a website when you were done just a bunch of files.

If all you want is content I suggest using a search utility
to delete the unwanted files, after the download is completed.

If you are having a problem of limited drive space, break the website copy
down into smaller projects.