unable to scale down mask

hi.

i created a mask in my footage by using pencil tool

now i want to scale it down (NOT to shrink/expand masked area)

tried this: selected footage layer and went to Transform - Scale, and even if i scale down to -500%, nothing happens. Then went to Mask - Mask Expansion, but this is not the feature i need. I need to scale down the object which i've masked out

also tried to add adjustment layer and linked my mask layer to it and then tried to scale down Adjustment layer - no effect, simply nothing happens

using AE6 trial version on win7