When next you upgrade sendmail, please compile it for loading milters (plugins). Also, the current AUTH mechanisms allow only plain text, not STARTTLS or CRAM-MD5 or any other encrypted authentication mechanism, thus I can't/won't relay my own mail from home through my domain's mail server, which is poor. Please enable encrypted SMTP AUTH mechanisms.

It has been a long time coming, but my sendmail has been upgraded to 8.12.11.20060308 (Released 2004/01/18, patched 2006/03/08) from 8.11.6 (Released 2001/08/20), which I guess is progress. However, while this version supports MILTERs, many milters require Sendmail 8.13 or later. I do not understand why Westhost have upgraded to an obsolete version; the latest stable version is 8.13.8 (Released 2006/09/08)

Some of the milters I have looked at must be started before Sendmail and shutdown after it. I am not sure how we would achieve this as Sendmail is controlled at the Server level, rather than the VPS level where we have control. However, sendmail is only started when communications is started on port 25, so we should be able to create the necessary startup command in /etc/rc.d/init.d

You also wanted SSL support. Issuing the command sendmail -d0.1 -bv tells us that Sendmail has been built with MILTER and SASL support, but not STARTTLS, so the password and login will still be passed in the clear (if I understand correctly) although the message will be encrypted between your computer and the server. A pity.