Configurating software POLICYD under a Linux Server

I have a Server, it is only for emails purpose, being pop / smtp to all our customers' mailboxes. This Server run Linux Centos, with Apache, Postfix, Postgrey, Spamassassin, Clamd, Amavis. And I also have a software called POLICYD, from [[login to view URL]][1]. All this stuff is working nicely. Well, I want to put limit to those accounts, so that each mail account (each mailbox, not each Domain) can send just, say, 500 or 1000 emails daily (within 24 hours or something like this). It would be a limit as GMail (Google APPS) puts to its accounts. All I need is to configurate POLICYD (I was told it has this facility). The package is already installed and running, and doing other tasks, but I was not able to set this kind of limit. This is what I need.