I've decided to install from scratch instead.
It took no more than 3 hours including download time to install Ubuntu 8.0.4 and Zimbra Open Source 6xx
and, this server runs a lot faster and smoother than the appliance.
for those that need assistance, check this link:
How To Install Zimbra Collaboration Suite (ZCS) On Ubuntu | HowtoForge - Linux Howtos and Tutorials