I have tested your scenario at my end. Unfortunately I am also unable to propose a solution. I have checked the MessageId and UniqueUri of message on Exchange, it does not match with the EntryId for the same message in PST.
I have logged an investigation and asked the development team for their opinion on this. The ticket Id for your reference is NETWORKNET-33183. As soon as I hear from them, I will let you know here.
Please accept my apologies for your inconvenience.
MapiMessage.InternetMessageId is the same as ExchangeMessageInfo.MessageId
But to get it I need to Extract message from pst-file (in case if I have 10 000 - 20 0000 messages in pst this will cause huge perfprmance problems).
If you could implement InternetMessageId property in Aspose.Email.Outlook.Pst.MessageInfo, this will be perfect solution for me. This will allow to compare new and already downloaded messages with minimum costs.
And also, is it possible to add ' receivedDate' to MessageInfo?
I have closed the investigative ticket logged earlier under Id NETWORKNET-33183 and created a new one to analyze the requirement of adding InternetMessageId and ReceivedDate properties to the Aspose.Email.Outlook.Pst.MessageInfo class. The ticket Id for your reference is NETWORKNET-33186.