Summary: http://technet.microsoft.com/en-us/library/bb125236.aspx

1. Export XML data.  http://technet.microsoft.com/en-us/library/aa997590.aspx
   New-EdgeSubscription -FileName "C:\EdgeSubscriptionInfo.xml"
2. Import XML data. http://technet.microsoft.com/en-us/library/bb123538.aspx
1. Open the Exchange Management Console. Expand Organization Configuration, select Hub Transport, and then in the result pane, click the Edge Subscriptions tab.
2. In the action pane, click New Edge Subscription. The New Edge Subscription Wizard starts.
3. On the New Edge Subscription page, in the Active Directory Site: drop-down list, select an Active Directory site.
4. On the New Edge Subscription page, click Browse. Locate the Edge Subscription file to import. Select the file, and then click Open.
5. On the New Edge Subscription page, click New.
6. On the Completion page, click Finish.
3. Force synchronization if necessary.
   http://technet.microsoft.com/en-us/library/bb123512.aspx
   If running RTM: Start-EdgeSynchronization
   If running SP1: Start-EdgeSynchronization -Server <Hub Transport server name>