How to say to the TexDraw brush to paint through an UV map?

I am on this basic thing from a week everyday.
I’ve watched MANY tutorials on YouTube but all are referring to Blender Render and so I don’t know if it’s possible in Cycles now.

I am using Blender 2.77, and Cycles.

I have my textures for each side of the object.
I have my Uv maps, projected from view.
I have connected the empty texture to the Diffuse Node, as target to paint on, and it is set as “Brush” texture.
I have set the TexDraw brush on Stencil, using the frontal texture.
In Slots, I’ve set Image as Painting mode, and the frontal UV map as Uv map, and the empty texture as Canvas.
I also tried all the options in Mask, who knows, just to try solutions.

But it doesn’t work.

It paints only the native flat image without passing through the mapping that I’ve selected in Slots.
And I want to paint the textures passing by my projected-from-view frontal UVmaps.
I also tried to not use Stencil.
Nothing.

PLEASE, HOW.
Thanks.