With this short blog, I would like to point you to another confusing statement that you can find in the article on http://technet.microsoft.com/en-us/magazine/ff472471.aspx:
If you just add the service account to the Exchange Recipient group, you will see the following error event in EventLog (and of course, the run profile will stop/fail with the error stopped-extension-dll-exception).
There is an error in Exch2010Extension BeginExportToCd() function.Type: System.Management.Automation.Remoting.PSRemotingTransportException
Message:
“Microsoft.MetadirectoryServices.ExtensionException: Processing data from remote server failed with the following error message: The user “<domain>/<ADMAAccount>” isn’t assigned to any management roles. For more information, see the about_Remote_Troubleshooting Help topic.
So based on the error, it’s clear that you have to add the account used for the Active Directory Management Agent to the Exchange Recipient Administrators group, instead of the FIM Sync Service service account.