I see, so it seems more complicated than I thought.
I asked the admin of the mail server and he said it's no problem to install a plugin when it's available. The Server will move to another platform during the next weeks, where the current version of RC is installed.
I Don't know if it's worth the effort, but the Notifier plugin is a good and easy to use tool, that can also handle multiple mail accounts and is updated frequently, so supporting it would be a good benefit in my opinion.