If you only have one server, I don't see how that will help you. You will still have to accept the root certificate on each of the clients.
SME should only renew it's default certificate once a year (or if the system name changes) so if you only have one server, just add it's certificate to your browser's trusted certificates and you should not get the error for a year. If you have too many machines to manually add the cert to each one, your best bet is to purchase a certificate from a company that has a valid root certificate already installed on your machines and you would never see the invalid certificate screen again.