or you could use modrewrite so you could alias index.html as index.php
i do this for tgp submissions that dont allow .php extensions that my gallery program creates.
so
http://www.domain.com/index.php would work as
http://www.domain.com/index.html
or in my case
http://www.domain.com/galleries/fuc/...sold/index.php
would work as
http://www.domain.com/galleries/fuc/...old/index.html
Code:
Options +FollowSymLinks
RewriteEngine On
RewriteCond %{SCRIPT_FILENAME} !-f
RewriteCond %{REQUEST_URI} ^(/.+\.)html$ [NC]
RewriteCond %{DOCUMENT_ROOT}%1php -f
RewriteRule \.html$ %1php [NC,QSA,L]
hope that helps