404 error works but not if there is index.php in title - Joomla! Forum - community, help and support

just re-say have in title, custom 404 error works great not if there index.php in title. example:

http://www.mysite.com/nopagehere <<< display custom 404
http://www.mysite.com/index.phpp <<< notice p, number, characters etc, in case, displays standard 404 page, not custom one.

thanks
lee

are using .htaccess 404 error handling?