Assembly: Microsoft.Office.Interop.Outlook (in Microsoft.Office.Interop.Outlook.dll)
Multimedia objects, including images, video, and audio items, can be added only programmatically as attachments to a MobileItem object that is a Multimedia Messaging Service (MMS) message. The inspector for the MobileItem object does not support adding attachments through the user interface.
To add multimedia objects to an MMS MobileItem object, use the SMILBody property. Specify URLs to these multimedia files in the Synchronized Multimedia Integration Language (SMIL) markup for that MMS message.