One of the things that I’ve taken a look at in the past is Citrix, from the point of view of getting the Enterprise Vault client installed. There is now a clearer statement in the Compatibility Guide which will help Symantec Support in the future :
Symantec provides client support for Citrix based thin client provisioning. This support is limited to the installation and use of the Enterprise Vault client for Outlook, excluding Vault Cache or Virtual Vault. Support for these features is a future requirement for the Enterprise Vault client. Symantec does not currently support any aspect of its Enterprise Vault server infrastructure provisioned via Citrix.
Link to the Guide : http://www.symantec.com/business/support/index?page=content&id=TECH38537