how to use httpd itk on centos 6.x

Run VirtualHosts under separate users

Enable the epel repository and:
yum install httpd-itk

vim /etc/httpd/conf.d/php.conf
<IfModule prefork.c>
LoadModule php5_module modules/libphp5.so
</IfModule>
<IfModule worker.c>
LoadModule php5_module modules/libphp5-zts.so
</IfModule>
<IfModule itk.c>
LoadModule php5_module modules/libphp5.so
</IfModule>

vim /etc/sysconfig/httpd
HTTPD=/usr/sbin/httpd.itk

Add a new user without a login shell and chown your site to it

and then configure your vhost
<VirtualHost 82.145.45.42:8080>
ServerName hostname.com
DocumentRoot /path/to/docroot

AssignUserId desired-user desired-user

<Directory /path/to/docroot>
Options FollowSymLinks
AllowOverride None
order allow,deny
allow from all
</Directory>
</VirtualHost>

Use different users for different sites to achieve the intended purpose.