Scale an object WITHOUT scaling the keyline?

I am trying to scale a box object on the state that I’ve used in different instances to highlight relevant information. The areas are all different sizes, and I’d like to use different instances of the same movie clip with the box object.

The problem is my box object has a 2px keyline around it, and when I scale my movie to fit the various areas to be highlighted, my keyline also scales, which is ruining the look.

Anyone know a way around this?