Is there a mail application for Mac OS X with S/MIME support and keychain integration other than Apple's Mail.app?
- Thunderbird has S/MIME but no keychain access (please correct me).
- MailMate has keychain access but no S/MIME.
- Postbox, although it claims to has good system integration, it does not as keychain access, but mozillastyle cryptowallet.
- Sparrow does not have S/MIME.