When sending attachments, AttachingIT stops sending the attached attachments back in the e-mail message in the Sent Items folder. For Office 365 users, this can lead to synchronization problems. Shipment statements have been created for this purpose.
Shipping statements are sent to a subfolder called AttachingIT under the shipped items. In this copy you will find the original sent e-mail, the sent attachments and a summary including the digital fingerprints of the files.
To activate this functionality, the ReAddAttachmentsAfterSent registry key must be set to 2. See here how you can adjust registry settings.