Here's one for Cricket -- I'm trying to use Mail.app to create a mime-encoded html newsletter embedded in an email for my Sunday School class. Mail.app doesn't appear to allow you to send mime-encoded embedded html email. If I could predict or set the boundary part, I could create the mime content in an external app outside the message and paste it into Mail.app. Is there any way to add a Mime-Content header manually so that I can use the designated boundary part identifier in my mime message?