I know it's late, but anyway here it is: $objEmail.Fields("urn:schemas:mailheader:x-mailer") = "My application Name or whatever else"   and here is the way how to set "code page" (here Czech) : this is important when you have chars with diacritics (special non-english letters) in your email $objEmail.BodyPart.ContentTransferEncoding = "8bit" $objEmail.BodyPart.CharSet = "windows-1250"