The installation / removal of whmXtra is easy
To remove WHMXtra do the following
wget http://whmxtra.com/pro/remitall.sh;sh remitall.sh
To install WHMXtra do the following ,
wget http://whmxtra.com/pro/pro.sh;sh pro.sh
Now logins to WHM -> Plugins and continue with the installation procedure
This tool is a commercial version, and license is needed. You can get it directly at WHMXtra website.