Here's the theory -
The .html file would override the .php file. Any subsequent links to index.php from within the vb system would go to the standard vB type index.php page.
I'm looking to do the same thing, only I want the user to see a different page based on whether or not they are logged in, so that if not logged in you get a splash page with login form (so it would need to be a php file) and a link to register or to contact admin if you've a problem registering. If you are logged in you'd get the standard CMS hme page. I'm kinda think for my needs I'd have to have an interstitial page to determine the user status so that they don't have to sit around while the not-logged-in page renders to be redirected to the right one.
I'm having no luck getting any help on that