I dont really know how shaders process the info.
I see that c.v.u2 hold the elumination value defined by the code.
Basically I dont need a shader dooing anything else
than drawing the textured Model normally (no extra effects, one texture skin enough)
and using the brigtness (as c.v.u2 defined here) for the
vertex.
Would be great if you could add this

Then I already have what I was looking for.