Hi,
I've verified this against my 8.x update training material which clearly states:
- Support for Un-Optimized Backup/Restore
- Support for Image Backup/Restore
- Optimized Backup/Restore is not supported
So with the current versions, that's what you have. Given Microsoft does provide an API for optimized backup, that may get supported in some future version of DP, but so far I've heard nothing of plans to do so. Solving the consistency issues may not be trivial, and it may be considered that it doesn't provide much advantages over image backup. But again, I don't really know, it's just a guess.
HTH,
Andre.