The system is linked to the ePO server the policy was exported from in only 1 way. The policy contains the ePO public key. If the switch is selected to create a recovery file, this file is encrypted using the ePO Public Key. In the event the machine needs to be recovered, the recovery xml file must be imported to that specific ePO server to be decrypted.
The ePO server (database) the machine connects to is based upon McAfee Agent. If McAfee Agent isn't installed, Drive Encryption cannot connect to ePO.