Hypermail has an escape convention whereby one can have literal
HTML in a mailgram and it will appear as HTML in the formatted
archive page. Not so with MHonArc.
To be MIME-clean you would want to send messages with the HTML as
an attachment. Could be marked an "inline" disposition attachment.
But then it gets its text/html type indication and MHonArc can
process it cleanly. The next step is [here I am in over my head]
to create a message/multipart handling capability in MHonArc which
honors "inline" disposition of HTML attachments and folds them
into the HTML document produced from the root RFC 822 message.
Warning: that is not the way the world is going. The
conventional wisdom is that mail clients (and hence archivers
like MHonArc) process messages as text/* and sniff for HTML tags
on suspicion that they may have a web-formatted document in the
message.
If it walks like a duck, they treat it as a duck and links are
clickable, etc.
If you want to do that, too, you have to modify the text/plain
mimefilter (sorry that is not its exact name) to sniff and
presume HTML on encountering a tag unless there is a DOCTYPE or
header to contradict this.
Al