We are working to set up a workflow that will create a task for users using Exchanage impersonation. I have set up the Exchange impersonation per
http://msdn.microsoft.com/en-us/library/exchange/bb204088(v=exchg.140).aspx
We entered the credentials of the impersonation account as a workflow constant and assigned them to the workflow we have for creating the task. I have imported/verified the root certificates are in the certificate manager on the SharePoint server, and we've added the certificates in the Central Management console for SharePoint. If I log on directly to the SharePoint server I can connect to the URL mention in the Microsoft MSDN article above without getting a certificate prompt error, and we are using that URL in our workflow setup. Still the workflow fails with the error "Failed to invoke Microsoft Exchange web service. Error returned from server: The underlying connection was closed: could not establish trust relationship for the SSL/TLS secure channel".
Is there a document somewhere that goes over all the specific configuration steps that need to be considered for integration with Exchange 2010?