Symantec Encryption Desktop does not currently support customized image on UEFI based systems. This policy option currently works with "only Windows clients booting in BIOS mode".
Symantec Corporation is committed to product quality and satisfied customers. This Feature Request is currently being considered by Symantec Corporation to be addressed in a forthcoming version of the product.
Technical Support team filed a Feature Request to add this product feature. Note that an feature request is exactly that, a request. There is no committed date for this request from the Endpoint Encryption Product Management team, nor from the Endpoint Encryption Engineering team at this time.
Please be sure to refer back to this document periodically as any changes to the status of the request will be reflected here.