Photoshop :: Rotating Animation With A Seamless Loop

I'm trying to do something very simple in PS CS6 that's proving to be, well, not so simple (for me at least). All I want to do is animate a layer in a clockwise direction and end up with a seamless looping animated gif. I discovered rotation can't even be animated unless you convert the layer to a smart object, first of all (and by accident. And the "Motion" function doesn't seem to work much at all, where there is a "Rotate" option.).

And of course simply copy-pasting the first key frame in the timeline to the end of the timeline just makes the layer rotate clockwise, then counter clockwise back to it's original position.