[imp] S/MIME support

[Todd Merritt]

I'm running imp 4.0, and having trouble using s/mime.  I have two
problems that I haven't found a solution to, the first is that I can't
figure out how to import other people's public keys under s/mime,
although I see where I can do it with pgp.  I'm able to send s/mime
signed messages, but I can't send encrypted messages.  The other is that
if I send myself and s/mime encrypted message in thunderbird, I can view
the message fine in thunderbird but when I go into imp I just see a
message with an attachment of type application/x-pkcs7-mime, but it
doesn't prompt for my passphrase to decrypt it.

    Any suggestions ?

Thanks,
Todd