When you enable fast-cgi, there should be a custom php.ini in the cgi-bin folder of the account.
* Just Move your php.ini file into the cgi-bin folder of the account
* In the cgi-bin folder, create php.fcgi and put the following in this file:
#!/bin/sh
export PHP_FCGI_CHILDREN=1
export PHP_FCGI_MAX_REQUESTS=10
exec /usr/local/cpanel/cgi-sys/php5
* chmod php.fcgi to 755.
* Upload .htaccess under public_html and put the following:
AddHandler php5-fastcgi .php
Action php5-fastcgi /cgi-bin/php.fcgi
Then save the file and this custom php configuration will now work.
Please note that .htaccess will still work the same way.