Flipping textures

I have two different gui texture elements:

1 x horizontal - this goes across my screen and has a horziontal texture applied to it. 1 x vertical- this goes up and down my screen and has a vertical texture applied to it.

I want to be able to take my vertical texture and apply it to my horizontal gui texture during game play but when I try to do this it come in the wrong way - it should come in as 512x256 but instad enters as 256x512 and looks very squashed.

Is there a way I can do this?

verticalGUI.texture = horizontalTexture; // This causes the image to come in with the   wrong orientation