SMTP Authentication Question

[Payne]

Guys,

I am a bit slow on this, I got a client that won't let me change the way 
mail working, but they want me to set up SMTP Authentication. How can I 
do it so it work without cyrus or dovecot. I question what is the very 
simple way of doing. Everything I have seen from goolge to 
howtoforge.com wants me to install like imap.

Thanks,

Chuck

PS. Links to how too are very welcomed.