Exchange 2013 SP1 Installation Error in "Mailbox Role: Transport service"

I tried an installation last week on a Windows Server 2008 R2 but was unable to get it to work. With the value of hindsight, I am inclined to think the error was more with the Web Site making EAC unavailable. I subsequently got it installed in my personal lab environment by creating a VM with a fresh install of Windows Server 2008 R2 SP1. 

With this information I then went back to the customer's site and installed a clean version of Windows Server 2008 R2 SP1 in a virtual machine under Hyper-V. After installing all the prerequisites the install appeared to be going just fine but then in failed in Step 7 with the following error:

The following error was generated when "$error.Clear(); 
          if ( ($server -eq $null) -and ($RoleIsDatacenter -ne $true) )
          {
            Update-RmsSharedIdentity -ServerName $RoleNetBIOSName
          }" was run: "Database is mandatory on UserMailbox.".

I know MS Exchange hides most of its information in AD so my suspicion is that the failed install on the real server has left some residual information in AD. Note that the original install on the real machine won't uninstall because the prior install attempt hasn't finished.

The relevant part of the Exchange Setup Log is:

[07/22/2014 14:22:57.0593] [2] Active Directory session settings for 'Update-RmsSharedIdentity' are: View Entire Forest: 'True', Configuration Domain Controller: 'AWSDC.aws.local', Preferred Global Catalog: 'AWSDC.aws.local', Preferred Domain Controllers: '{ AWSDC.aws.local }'
[07/22/2014 14:22:57.0593] [2] User specified parameters:  -ServerName:'EXCHANGE'
[07/22/2014 14:22:57.0593] [2] Beginning processing Update-RmsSharedIdentity
[07/22/2014 14:22:58.0031] [2] RMS Shared Identity user 'CN=FederatedEmail.4c1f4d8b-8179-4148-93bf-00a95fa1e042,CN=Users,DC=aws,DC=local' (originating server = 'AWSDC.aws.local') is being linked to computer 'CN=EXCHANGE,CN=Computers,DC=aws,DC=local' (originating server = 'AWSDC.aws.local').
[07/22/2014 14:22:58.0156] [2] [ERROR] Database is mandatory on UserMailbox.
[07/22/2014 14:22:58.0156] [2] Ending processing Update-RmsSharedIdentity
[07/22/2014 14:22:58.0156] [1] The following 1 error(s) occurred during task execution:
[07/22/2014 14:22:58.0156] [1] 0.  ErrorRecord: Database is mandatory on UserMailbox.
[07/22/2014 14:22:58.0156] [1] 0.  ErrorRecord: Microsoft.Exchange.Data.DataValidationException: Database is mandatory on UserMailbox.
   at Microsoft.Exchange.Data.Directory.ADDataSession.Save(ADObject instanceToSave, IEnumerable`1 properties, Boolean bypassValidation)
   at Microsoft.Exchange.Management.Deployment.UpdateRmsSharedIdentity.Link()
   at Microsoft.Exchange.Management.Deployment.UpdateRmsSharedIdentity.InternalProcessRecord()
   at Microsoft.Exchange.Configuration.Tasks.Task.ProcessRecord()
[07/22/2014 14:22:58.0156] [1] [ERROR] The following error was generated when "$error.Clear(); 
          if ( ($server -eq $null) -and ($RoleIsDatacenter -ne $true) )
          {
            Update-RmsSharedIdentity -ServerName $RoleNetBIOSName
          }
        " was run: "Database is mandatory on UserMailbox.".
[07/22/2014 14:22:58.0156] [1] [ERROR] Database is mandatory on UserMailbox.

Does anyone have suggestions about what to do with ADSI Edit to fix the problems?

I think I am getting close to having a working Exchange!!