First lead :
I see that Zimbra installs the Connector as an Outlook Component for Exchange.
Is there a mean to bypass the ZCO MSI and to install it through Outlook directly (but with command lines and silently)?
Second lead :
I succeeded in installing the ZCO through a new MSI of mine.
But there is an error when I try to get the install clean with a removal (to get the user environment clean back).
It lets the Component in Outlook active and get this error :
Translation : "Impossible to load the 'Zimbra Client Extension' component (SharingAddin.DLL), which was disabled by Outlook. Contact the component furnisher to obtain an update. If no update is available, uninstall it completely."
I can solve the problem in unchecking the "Zimbra Client Extension" option in the Outlook Component Manager (Exchange client extensions) :
If you give me the registry key to be changed or deleted, I think I can manage the Install/Uninstall as SYSTEM.