TMT does not support bitstreaming with the 460 at this time. NVIDIA has not even released the drivers yet required to impliment it. We may support it in the future but it will either be announced via marketing or appear in the app before it is discussed here so basically asking if/when here won't be of much value as neither will be confirmed.
(WinDVD uses a workaround for their bitstreaming support which is not used by TMT, would not be straightforward to impliment, and would have other side effects. This doesn not mean it's off the table as a future possibility.)