Leave at least one Microsoft Exchange server with Hub, CAS, and Mailbox roles in the environment.
Customize the Web Interface to create an interface which exposes any desired attributes.
NOTE: Merely exposing some attributes may not be sufficient. With no Microsoft Exchange server in the environment, there will be different logic governing the behavior of some attributes, especially those which are related to email. Custom Workflows and Policies may be required in order to achieve the desired results.
For assistance with implementing customizations in your Active Roles configuration, contact your Account Rep for information on engaging Consulting Services or you may visit our Consulting Services page for further information, or engage the Active Roles Communities here.