the scripts should be available to end user and not to the administrator, in cpanel and plesk the one click applications are made thru the end user (the customer) and not the admin, here in our case that i buy virtualmin pro to be available only to admin is mistake
They are not available only for the admin. Domain owner users can also install scripts. The root user, of course, always has all privileges, but you can grant domain owners the ability to install scripts (and just about anything else related to their domains).