Specifies the RefToMessageId in the message.
This property specifies the RefToMessageId value in the message being sent.
This property is only applicable when Profile is set to pfESENS. The e-SENS profile supports the Two-Way/Push-and-Push MEP (Message Exchange Pattern), where sending a file can be in reference to a previously received file. In this case RefToMessageId specifies the Id of the previously received message to which this send is in reference.
This property is not available in the Receiver.