How do you visually rotate a masked shape in the Composition window instead of doing it by changing the values in the layers panel?
Might the Rotate-Tool be the solution to your problem? (Press W to activate it.)
You can double click on a path control point to bring up the transform tool for all points on a path or you can shift select or with the pen tool selected drag and select multiple points then double click to bring up the transform tool, then move to any corner and rotate the transform box. This video demonstrates the technique of editing and transforming multiple points. You'll have to watch closely but it shows how to do it: