We use Lotus Notes mail as the primary client for POP3 and SMTP mail at home, and the one functionality missing is mail rules. As you know, the mail rules in Lotus Notes run on the SMTP server, and you do not have mail sorting without the Domino SMTP server. Although this tool is not perfect, it does show how to use Eclipse to extend Lotus Notes and to use the Lotus Notes Java backend classes for accessing and manipulating Lotus Notes data.
The original article can be found here on IBM's Developer Works-> http://www.ibm.com/developerworks/lotus/library/notes8-mail/index.html.
Install the latest widget using this extension.xml.