2.1.3.5.1 Generation Process
Generating a pure MIME message using the saved Message object contents in conjunction with the PidTagMimeSkeleton property ([MS-OXCMSG] section 2.2.1.28) follows these steps.
The contents of the PidTagMimeSkeleton property are combined with the saved best body and message attachments from the Message object, using the order of the headers from the PidTagMimeSkeleton property to place the message contents in the original order in the generated message.
Use the Content-ID (or X-ExchangeMime-Skeleton-Content-Id) header in the PidTagMimeSkeleton property to map the MIME attachment to the message body part with a matching value of the PidTagAttachContentId property ([MS-OXCMSG] section 2.2.2.29).
Use the Content-ID (or X-ExchangeMime-Skeleton-Content-Id) header to map the MIME body part to the message body part with a matching value of the PidTagAttachContentId property.
The following headers are ignored in the skeleton and are regenerated from Message object properties:
Keywords
Importance
Priority
X-MsMail-Priority
X-Priority
X-Message-Flag
The MIME-Version header MAY<105> be ignored in the skeleton and be set to "1.0".
Encode attachment content using the Content-Transfer-Encoding header value specified in the headers for the attachment in the PidTagMimeSkeleton property. If the specified Content-Transfer-Encoding header is not supported by the server, then use the default base64 encoding for the attachment content and modify the value of the Content-Transfer-Encoding header in the PidTagMimeSkeleton property and in the outbound message to reflect this change.
The X-ExchangeMime-Skeleton-Content-Id headers SHOULD be deleted from the generated MIME message.