2.3.3.3 attFrom Attribute Handling by the TNEF Reader
When reading the sender-email field of the attFrom attribute, as specified in section 2.1.3.3.3, the TNEF Reader MUST set the PidTagSenderEntryId property ([MS-OXOMSG] section 2.2.1.50) and SHOULD decode the attFrom attribute into the other PidTagSender_XXX properties, as specified in section 2.1.3.1.1.