Hi Ralph,
I don't know, but replacing one MIME part in an email sounds like it's
in mhfixmsg(1)'s domain. Perhaps it could grow some kind of filter-part
option whereby application/pkcs7-signature can be specified and the
command used to filter looked up, just as mhfixmsg-format-text/html is
now.
(I've often thought a delete-part would be useful for all those
corporate-signature images tacked onto the end of every email.)
I agree with both. As far as implementation goes, I won't have time in the
near future but would be glad to review patches, etc.
David