Hi Spa,
I was working with someone on a very similar problem back in May 2007 who sucessfully did this type of change and we just did this exact change using the Cisco recommended method;
You should be good to go with this plan.
Replacing the Publisher Database Server After the Installation
To replace an existing or failed server, perform the following steps:
1. Install the operating system and the Cisco CallManager software as if it were a new installation by using the Cisco-provided operating system disks and the operating system documentation.
2. Upgrade to the version of the Cisco CallManager that you want to restore.
3. If necessary, reinstall the Cisco IP telephony applications, plugins, and service releases to the version that is compatible with the restored version of Cisco CallManager.
4. To obtain the locales that were used prior to the restoration, reinstall the Cisco IP Telephony Locale Installer.
5. Restore the backup data to the new server and reboot the server.
To restore the data, you must have backup data stored on tape or on a network directory, not on the local directory of the existing or failed server.
6. Verify that the data was restored to the new server.
7. If you are replacing a server with four drives, Cisco recommends that you set the trace directory path on the server to the default C: drive before you backup your server.
8. If your server has four drives, you can configure the trace drive for trace file collection.
From this doc;
http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/install/4_1/cm413ins.html#wp534959
May thread;
http://forum.cisco.com/eforum/servlet/NetProf?page=netprof&forum=Unified%20Communications%20and%20Video&topic=IP%20Telephony&CommCmd=MB%3Fcmd%3Ddisplay_location%26location%3D.1dde6a72
Restoring Subscriber Servers
When you perform a server replacement, you must always manually enter the IP information, computer name, and other configuration data exactly as it was entered on the original server.
Make sure that you locate the configuration information for this server before you begin.
Cisco does not require that you remove the subscriber server from the Cisco Unified CallManager database before recovering the server. When the subscriber server authenticates to the publisher database server and pulls a duplicate of the database from the server, the subscriber server automatically adds itself to the database.
If you are reinstalling a subscriber server only, you did not need to do a BARS restore unless the CDR and TFTP data on this subscriber server was backed up with BARS and now needs to be restored. The subscriber server will acquire all Cisco Unified CallManager configuration data from the publisher server.
Use the following guidelines to restore the subscriber server(s):
Perform a new installation of both Cisco Unified CallManager and the Cisco-provided operating system:
For Cisco CallManager 3.3(3), as the minimum required operating system, use version 2000.2.3 with an upgrade to 2000.2.4 or a fresh install to operating system version 2000.2.4.
For Cisco Unified CallManager 4.0, 4.1, and 4.2, as the minimum required operating system, use version 2000.2.3 with an upgrade to version 2000.2.5. Ensure the operating system is also SR2 or later.
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Note The version of Cisco Unified CallManager must match the version that is running on the publisher database server.
Here is a good doc that has all the info for doing Backups and then restoring on the new box;
http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/bars/4_0_11/ag-4011.html
Hope this helps!
Rob
