You can turn off canonical redirection by putting this into your plugins directory:
/*
Plugin Name: Disable Canonical URL Redirection
Description: Disables the "Canonical URL Redirect" features of WordPress 2.3 and above.
Version: 1.0
Author: Andrei Volkov
Author URI: http://upwork.link
*/
remove_filter('template_redirect', 'redirect_canonical');
From http://txfx.net/files/wordpress/disable-canonical-redirects.phps.
This should turn off that feature. Whether or not your setup will work as you need is another thing.
FINALLY: You want to run your wordpress installation at yourdomain.com/index.php but also want to use yourdomain.com/index.html. Both of these URLs should work at the same time and there should be no redirect from index.php to index.html.
Here are the steps for newbies:
- Open your site with an FTP program
- navigate to /wp-content/plugins/
- create a new folder of any name
- create an index.php and put the PHP code above and copy to your new folder
- visit your wordpress backend and activate this new plugin