What it does:
Replaces one color with another.
How to use it:
The "old" parameters define the color to be replaced, and the "new" parameters define the new color. Values are in the range from 0 to 255.
Installation:
Download "Color Replace.fx" and place it inside the effects folder.
Download:
Color Replace.fx
old:http://dl.dropbox.com/u/5426011/Color%20Replace.fx
EDIT:
New version that works with transparency, thanks to tulamide