The postfix package *does* have an SMF manifest for the postfix service, but it:

1. Uses `/opt/omni/libexec/postfix/master` to start instead of `/opt/omni/sbin/postfix start` (postfix's recommended method of starting).
2. Uses `:kill` to stop, rather than using `postfix stop`.
3. Points to a config file that doesn't exist (`/opt/postfix/main.cf`).

So, we drop off our own here and load it up for the service.