Gigatron, 
zenox98 The disappearing issue was a mistaken of mine, i think, sorry....but that color problem remains, even with this parameters.....I can resolve this adding a blend luminosity fx and changing BG color, but is not an appropriate solution...The Demo you posted with the slider bars is perfect... but i haven't found the capx inside the rar file... (although i think it doesn't resolve )
I have the same problem with color