How do i use Adjustments to edit a Layer Mask in cs5?

i want to use the adjustments to modify a layer mask, and I want to be able to preview the changes as i make them.

In PS7 it was just as straightforward to apply Adjustments to the mask as the image itself.
you could just click on the mask's thumbnail then go to Image>Adjustments and all the same options would be available. but not with cs5!

can anyone help?

thanks