I think the correct phrase is "OMG OMG HELP!?! NOW! ... please"
Jokes aside, clippingnode is a bit of a leftover from the pre-shader days, so it is limited in functionality. One limitation being that pixels are either processed or discarded, potentially resulting in some aliasing.
You would most likely have to look into more recent ways of doing things, like multi-texturing, or in worst case multi-stage rendering.