PGP ADK and EV

EV has a plugin called Secure Messaging and Rights Management which essentially allows EV admins to search through PGP encrypted emails.  You need to upload an ADK to the EV server which is fine.

How does something like this handle INCOMING encrypted emails into the vault?  How do external parties encrypted emails get viewed?  Can we somehow bundle in the public half of the ADK into all our users public keys so that incoming email is encrypted to the user AND our ADK?