We provide a web service that can email invoices and statements from our servers to our users customers. Our users have asked us that all emails sent from the web-service are also stored in the Sent Folder of the person using the web service.
We know the users email, and we could insist they provide us with IMAP access credentials.
What options do we have for saving emails sent by a user from our server in the Sent Mail folder of that user?
(hope that makes sense. It was pretty hard to explain)