2.2.1.56 PidTagSentRepresentingEntryId Property
Type: PtypBinary ([MS-OXCDATA] section 2.11.1)
The PidTagSentRepresentingEntryId property ([MS-OXPROPS] section 2.1015) identifies an address book EntryID, as specified by the address book EntryID ([MS-OXCDATA] section 2.2.5.2), that contains the identifier of the end user who is represented by the sending mailbox owner. If the sending mailbox owner is sending on his or her own behalf, this property is set to the value of the PidTagSenderEntryId property (section 2.2.1.50).