If you don't see what you need at https://assets.nagios.com/downloads/nag ... olist.html
then you should file a feature request at https://github.com/NagiosEnterprises/na ... issues/new
If you think this is better suited for a plugin, the plugin development guidelines are at http://nagios-plugins.org/doc/guidelines.html
I hate to be the bearer of bad news, but there are a number of security vulnerabilities that have been fixed since 4.0.7. I would highly advise upgrading to 4.2.4. Also, RHEL 5 goes EOL in March, so if you haven't already, it's time to migrate off of that.