Oliver Sommer 
2008-10-10
To qualify EBS customers for Unified Messaging (Exchange 2007 UM role) you need to
- install and configure the UM role using the EBS Messaging server media
- aquire Exchange 2007 Enterprise CALs for all users using UM
This is covered in several well known postings in various Exchange blogs and in Technet, so I am not gonne cover that for now here.
The EBS specialty about using the UM role on the Messaging server is about Reinstall / Replacementmode setup of Essential Business Servers Messaging servers that have UM installed and configured.
UM has to be deleted out of the AD to be able to use the cool EBS unique feature of replacement mode setup:
To resolve this issue and allow setup to proceed, use the following steps to manually remove the UM configuration data from Active Directory:
1. Open Adsiedit.msc tool
2. Expand Configuration partition
3. Expand Services
4. Expand CN=Microsoft Exchange
5. Expand CN=
6. Expand CN=Administrative Groups
7. Expand CN=Exchange Administrative Group (FYDIBOHF23SPDLT)
8. Expand CN=Servers
9. Right-click on CN= and click on Properties
10. Locate the attribute msExchCurrentServerRoles property and click on the Edit button
11. Change the value from 54 to 38.
12. Save the settings and close ADSIEdit
13. Reboot and restart setup.