Hello,
FYI:
Dim MyMapiMessage As MapiMessage = MapiMessage.Load(str, loadopt)
MyMapiMessage.Headers.Set("X-Mailer"...
Dim SignedMessage As MapiMessage = New Email.SecureEmailManager().AttachSignature(MyMapiMessage, MyC…...seems most of the times many properties of the messages are lost/changed...AttachSignature , several message properties—such as categories, flag...