I generated a self-signed root S/MIME certificate using Certificate Assistant. I made sure the resulting certificate was in my Keychain, and trusted it explicitly. In attempts to send encrypted mail to that account the encryption icon is never activated and the certificate does not show up on the TLS certificate list for the account (Mail Preferences). I've also tried creating a Certificate Authority and using that to generate a leaf S/MIME certificate, with the same results. I found detailed instructions for setting up server and client certificates at
but, following those instructions, trying to adapt for S/MIME, produced the same result.
Signing mail from that account works fine.
Is there any way to do this?