Lotus Notes is one of the only email servers which doesn't have a Sent folder, which makes it difficult for SaneBox algorithms to calculate importance of messages. In addition, the SaneRemindMe feature won't work at all as it relies on being able to access your Sent folder.
Here's how to create the Sent folder in Lotus Notes:
- Directions for how to populate a Sent Items folder automatically going forward: http://www.ibm.com/developerworks/lotus/library/ls-Creating_a_Sent_Mail_folder/
- Directions for how to populate the Sent Items folder with historic email: http://www.csom.umn.edu/assets/92839.pdf