Re: Sending attachments

    > Is there any facility that can be used in Mail mode
    > to put attachments into the message?

    Use message-mode.

There was no reason to add Message mode to Emacs at all.
Someone decided to write a duplicate mode instead of
improving the one we had, and snuck it into Emacs without
submitting the decision to discussion.

Perhaps I will merge the relevant code from Message mode
into Mail mode.