BES, Exchange 2010 Hosting Mode and EWS Impersonation

I speak with a lot of people about getting BlackBerry Enterprise Server 5 working fully with Exchange Server 2010 Hosting Mode, and repeatedly come across the same problem with calendars.

While Microsoft have done an excellent job documenting Exchange Management Shell Cmdlets, RIM seems to have completely missed required sections from the deployment documentation.

With Exchange Server 2010 SP1 BES must use EWS to access calendar, to configure the service account we need to create a new Management Role.

New-ManagementScope -PartnerDelegatedTenantRestrictionFilter {Name -eq '*'} -Name BESTenants

New-ManagementRole -Parent PartnerDelegatedTenantManagement -Name BESEWS

New-ManagementRoleAssignment -Role BESEWS -User "BESAdmin” -CustomConfigWriteScope BESTenants

One thing I have been surprised by is few of the automation and control panel vendors are properly documenting this which to me suggests they may be missing steps in validating their solution.

What is your experience with Exchange 2010 /Hosting and BES?