[CentOS] Postfix Question

I've googled around and although I get a lot of hits about postfix
smarthost authentication with ssl, I can not find out how to
actually accomplish the task.

I've read through smatterings of postings from Neophasis and the
like searching for just the syntax and what file (I assume it's
main.cf) I should be using; however, any smtpd_ lines I have tried
result in postfix hanging and refusing to deliver mail.

I could simply cease using smarthost, but my ip address is dynamic
(yes I know stop yelling at me I'm poor right now) so mail bounces
to some domains if I don't use smarthost.

The server I'm running postfix on is CentOS 4 (fully updated).
Postfix version is 2.2.10-1.1.el4 (from rpm -qa). I have not had
sufficient downtime to upgrade to CentOS 5. Should I do that?

Sincerely

-- 
Alex White
ethericalzen at gmail.com
Life is a prison, death is a release