The procedure of MIME header analysis for "application/mac-binhex40" attachments is the same as for the procedure for ordinary file attachments that is specified in section 220.127.116.11.1, with the following exceptions:
Processing of the MIME body SHOULD include parsing a binary structure of the decoded content, as specified in [RFC1741]. MIME readers SHOULD<181> use the header and resource fork data from this structure to fill the PidNameAttachmentMacInfo property ([MS-OXCMSG] section 18.104.22.168) with appropriate data, as specified in section 22.214.171.124.2.1. MIME readers SHOULD also use this data to fill the MacBinary structure, which SHOULD<182> be written to the value of the PidTagAttachDataBinary property ([MS-OXCMSG] section 126.96.36.199).
MIME readers SHOULD<183> copy the attachment file name that is extracted from the BinHex structure to the value of the PidTagAttachFilename property ([MS-OXCMSG] section 188.8.131.52), but only if no file name was found during analysis of the MIME headers.<184>