Skew - IDE first, then code

I’m wiriting some code to read certain properties of a keyframed movieclip animation. The idea is that an animater will create an animation, the code will record the animation as it plays, then the numberd that have been saved can be used later.

x, y, rotation, xScale and yScale all did swimmingly well. skewX and skewY come out as undefined, on every frame. They’re both used in the movie (typically around 4 - 8 degrees). They’re never the same as each other.

What can I do to get these values?