Opposite direction possible?

Hello there, I would like to know, if it is possible to turn the parallax effect in the opposite direction (than the default). I think you could a create pretty awesome effects. For example: When horizontal parallax is enabled the BG-Image moves from left to the right side, when you scroll down. Is it possible with some code to let the BG-imgae move from the right to the left side, when you scroll down?

Thanks again for this great plugin.