After a lot of waiting (I run gentoo), I finally managed to get zimbra up and running with the help of this tutorial: http://forums.gentoo.org/viewtopic-t...ht-zimbra.html
The solution is to install the debian release in a chroot under gentoo, and while it's qurky, it runs good enough.
I can send and receive mail to/from the internet, and between zimbra accounts on the same machine, but I can't send email from php scripts, they end up in gentoo's queue (I turned off postfix to prevent from conflicting with zimbra).
I tried putting
sendmail_path = /opt/zimbra/postfix-2.2.9/sbin/sendmail
in php.ini but still no luck. I can't send email from php no matter if I try sending to a local, zimbra managed address or to an outbound, internet email address...