SharePoint 2013 eDiscovery with Exchange 2013

We are implementing SharePoint 2013 eDiscovery. One of the features is to be able to search Exchange 2013 e-mail boxes. If you are migrating from 2010 to 2013 as we are and have both Exchange 2010 and 2013 in your environment, be cautious of one thing. In order for a user to search 2013 e-mail boxes from SharePoint eDiscovery center, their e-mail box MUST be migrated to Exchange 2013. Don't expect Microsoft's "Premium" support to help you with this. We spent 5 hours with them before discovering this ourselves. Just be sure that any eDiscovery users are migrated before you try to search Exchange 2013 e-mail boxes.