Stage3D - reverse/flip texture

Hi, I’m building a simple platform game with Stage3D (not using Starling) and I’ve got a right facing texture for the main character. This works fine for when the character is walking right, but when they start walking left I’d like to use the same texture in reverse - however I can’t get this to work.

I’ve tried reversing the UV co-ordinates but this doesn’t seem to have any effect as the character still faces the right.

Is there any way to do this without resorting to having a second sprite sheet of all the frames in reverse?