Rebranding and Themes
From Zimbra :: Wiki
Open Source users can find instructions about modifying themes at Customizing_Themes_and_Adding_Zimbra_Inside_Logo_-_Open_Source_Edition
Additional information about the license usage can be found on the Zimbra web site, .
If you are a network edition customer, please contact your sales representative or support for instructions about rebranding and adding your logo. Additional documentation can be found at Creating_Themes_Long_Version & Skins in ZWC 5.0