I have set up in ubuntu, just not with what comes with Elastix. I am hoping that someone might have done it already. Clamav and spamassassin are kind of standard with postfix for a proper mail server setup.
i guess someone may do it before with Elastix, but I am sure someone allready did it with CentOS and there is more doc with CentOs than with Elastix. Remember that Elastix actually uses CentOs, and there is a lot more people using CentOS for mail server than Elastix.
Anyway, when you do it, it would be nice to share a how to