2.1.3.3.2 Message Body in TNEF

When generating a TNEF message, MIME writers SHOULD identify the best body property of the Message object, as specified in [MS-OXBBODY], and copy its value to the attMsgProps attribute, as specified in [MS-OXTNEF] section 2.1.3.3.21, of the TNEF body part. MIME writers also place a plain text version of the message body in the first child body part of the TNEF message, as specified in section 2, generating plain text from the value of the best body property if the best body format is other than plain text. Finally, when the best body is plain text, MIME writers SHOULD<66> also write a matching value for the PidTagRtfCompressed property ([MS-OXPROPS] section 2.942) to the attMsgProps attribute of the TNEF body part.