Inverted World Tracking Placement

Hi All, I have a simple request, I am trying to figure out how to invert the World Tracking Placement motion so instead of tilting forward/backwards to scale up/down, you can make it opposite, so tilting backwards scales up, and tilting forwards scales down instead.
I hope that makes sence.

I am sure it is simple enough to do, I just cannot figure it out.

Thanks,

Tim