I use Natty before, and it is detect my TV. When I click to the display tool, it is said I need to use the nvidia-settings. And it is works well. I use disper to change the X between my screen and my TV.
But in Oneiric display tool doesn't said I need to use the nv-settings. I think it is want to manage it. But in that situation the display tool doesn't detect my TV. And because it is manage my displays, disper doesn't detect too.
(Sorry for my english, I hope you can understand it.)