In Exchange 2007 there are quite a few well-known and widely used features that have been either discontinued (like OMA), or have been de-emphasized (like public folders) which means that the feature may not be supported in the next release of Exchange. Another de-emphasized feature is streaming backups. With the release of Service Pack 1, it became clear that it is no longer possible to take a remote streaming backup of an Exchange 2007 database running on Windows 2003 nor Windows 2008. It is however possible to re-enable the support of taking a remote streaming backup, if your Exchange Server 2007 Sp1 is deployed in a Windows 2003 OS by adding the following registry key and setting its value to 1:
Location = HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MSExchangeIS\ParameterSystem
DWORD (32-bit) Value= Enable Remote Streaming Backup
Value = 1
No need to restart any service, remote streaming backup is enabled, and will work. If you have deployed your Exchange 2007 environment on top of a Windows 2008 server, you won't be able to take a remote streaming backup, and Windows Backup 2008 doesn't include a streaming Exchange agent anymore. Therefore you will need to turn to VSS tools, like SCDPM 2007, or you could deploy a local streaming backup agent on your Exchange server and take a local streaming backup.