2.2.3.7 attMessageID Attribute Handling by the TNEF Writer

For compatibility, when generating a TNEF stream, the TNEF Writer MUST translate the binary representation of the attMessageID attribute, as specified in section 2.1.3.3.6, into a textual one by emitting the two CHAR hexadecimal equivalent per OCTET (i.e. %x01 becomes "01", %x2D becomes "2D", and so on).