Try check this guide:
If you have all in same server (apache / mail / database / dns / etc...)
This guide help alot.
If you did dedicated multiserver setup, you will need start set the things by hand on:
To point for your mail server...
After phew tests before i give up (was using dedicated multiserver setup), there some issues with permissions to enabling the features...
Setting arent saved... (you need make the file using root on shell - i have tried chmod 777 and dindt worked...)
And other stuff
I`m focusing now in one dedicated server with all stuff, if i get this working without any issue i come back to report.