Thankfully, I found a blog post by Karl Foley at http://cs.thefoleyhouse.co.uk/blogs/karl/archive/2008/02/10/how-to-backup-exchange-2007-on-server-2008.aspx. I followed his instructions and have re-posted the solution here:
1. Create a directory on the Windows 2008 server - C:\Program Files (x86)\NTBackup
2. Copy the following files from a Windows 2003 Server to the NTBackup directory on 2008 Server:
- c:\windows\system32\ntbackup.exe
- c:\windows\system32\ntmsapi.dll
- c:\windows\system32\vssapi.dll
Lastly, you will need to copy this file from an Exchange 2003 installation:
- c:\program files\exchsrvr\bin\esebcli2.dll
3. On the 2008 Server, install Removable Storage (Start Server Manager, Click Features, Add Features, Check Removable Storage Manager, Click Install).
4. On the 2008 Server, make a small registry change to HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\BackupRestore\DLLPaths
Change the path C:\Program Files\Micrsoft\Exchange Server\Bin\esebcli2.dll to C:\Program Files (x86)\NTBackup\esebcli2.dll.
Now, start NTBackup.EXE. You will see a notice that NTBackup cannot see Removable Storage but just ignore (and click the box to ignore forever if you don't want to see it again). When NTBackup starts, you should see your Exchange 2007 instance in the list of junk that you can backup.
Choose the Information Store(s) for your Exchange 2007 Server and back them up to a file on the hard drive.
Problem solved. Thanks Karl!
