The message number on the incoming mail server.
MailMessageNumber specifies a number between 1 and MailMessageCount, and serves as a message pointer to an incoming mail message. Properties such as MailMessageHeaders, MailMessageDate, MailMessageFrom, etc., allow you to determine if this message is an AS1 message. Additional properties are exposed via the Config method.
If this message is an AS1 transmission, you may use ReadRequest to read it. The Request and RequestHeaders properties will contain the request and request headers, and From will be populated with the originator of the request. You may then set trading partner information and invoke ProcessRequest to process the request.
This property is not available at design time.