Hi David,
Thank you for your interest in Aspose products.
Please note, when sending messages with Aspose.Email.ExchangeClient or ExchangeWebServiceClient the Exchange Server sends a copy to the "Sent Items" and got picked up by the Outlook application. Whereas, in case of a sent message via SMTP that is configured on an Outlook, the Outlook itself copies the message to the "Sent Items".
In your application, Aspose.Email just implements the SMTP protocol to send messages. It has nothing to do with adding it to "Sent Items", if the same account is also configured on an Outlook. So I am afraid, it will not be possible without an Exchange Server.
Babar Raza
Support Developer,
Aspose Sialkot Team
http://www.aspose.com/
Aspose - Your File Format Experts