Phoenix,
you have been quite clear, but seems CentOS is still pain in the ass for me. Actually, BIND has been pain in the ass, which I finally managed to install and to resolve names just inside ZIMBRA server...but still no luck
Which is why I switched to Ubuntu 9.10 server edition...
...and had some digestion problems here, too, since I overlooked Zimbra editions - for Ubuntu 8.04 only.
Ok, reinstalled with Ubuntu Server 8.04, with default settings, just 2 libraries to add...and Voila! Zimbra is up'n'running in no time
thank you for help anyways...hope it helps somebody else.