In these cases, new message are highly dependent of header/footer contents and should not keep content-transfer-encoding, I believe. Possible work around is to use ASCII only in header/footer.
Also, if you want to process the delivered message automatically, your program should be prepared for MIME encoded message. This, we have done for automated processing of -request messages.
These are not what you have asked before.
In these cases, new message are highly dependent of header/footer contents and should not keep content- transfer- encoding, I believe. Possible work around is to use ASCII only in header/footer.
Also, if you want to process the delivered message automatically, your program should be prepared for MIME encoded message. This, we have done for automated processing of -request messages.