When SuPHP is used regular apache2 directives are ignored.Directives have to be redirected to php.ini file.
To accomplish this use .htaccess file in vhost and use the redirect* line in it

Or as in my case add the redirect* line in ISPconfig2/3 apache directives.

Redirect* line:



To update this:ISPconfig3 Is now updated so use custom php.ini or apache directives tabs to add custom lines with out any need of redirection . So in this case my above suggestion is absolute.