I managed to make a work around for those with cards that only support regular PS 2.0, but it uses two shaders instead of one. The first one, "TPHUE Convert" converts the RGB values of an image into HSL, then the second one, "TPHUE Change Hue" changes the hue and converts the values back to RGB. They HAVE to be in the order specified, otherwise you'll get some funky results. Two Part Hue Shader
NOTE: Only use this shader if you're card doesn't support PS 2.0a. If it does, use the already linked to shader.