Using a file extension (.htm) in Views contextual filter path When I add a file extension after the contextual filter in my view's path it no longer works. The path with wildcard is: "section/%.htm"; can this be done or do I have to write some custom PHP to trim the URL of the file extension?

Please note that this is a legacy site which is rolling out section changes in phases, so there can be absolutely no URL changes while we convert the site to Drupal.
Why not use the redirect module (or just plain ol' .htaccess 301 redirects) to redirect /section/file.html to /section/file ? 

I understand the client doesn't want URLs to change, but doing a proper 301 redirect would preserve any SEO rankings they are trying to retain.