You need to make sure your account in Zimbra is provisioned to allow "Mobile" access. Once that is done, you need to create in EAS "Exchange Activesync Server" account in Versamail on your phone. You should be able to put in for server name the same address that you use on the internet to access Zimbra webmail. Use your same credentials and you should be good to go.
Release 6.0.2_GA_1912.UBUNTU8_64 UBUNTU8_64 NETWORK edition + Mobile Option
Activesync with Moto Q9C, HTC Touch Pro, Palm Pro, & Palm Pre