Yeah, yeah I know it’s not supported and doesn’t work out of the box, but hey just got it to work, and it was dead simple.
Basically get hold of the 64bit versions of ntbackup.exe, ntmsapi.dll, and vssapi.dll from a Windows 2003 server.
Now create folder on a Windows 2008 server that has the mailbox role installed and copy the files to it.
Now just run ntbackup.exe … sweeeeeeeeeet it works and can see the Information Stores!
Check out these two links for any more info: