Is it possible? is it maybe possible to change the compass poles in an exterior cell?

I spent a day making a heightmap and designing the landscape, not taking into account the sun's position. I need sunlight on 1 side of a mountain, instead it's on the other side most of the day.

Putting the sun more towards the center of the sky would also work.

Hmmm, I may be wrong but I think how the sun rotates about the sky is hardcoded and cannot be changed.

Try changing one or more of the fSun[variable] settings under Gameplay perhaps? There was a way to play with the settings and appearences in Morrowind/Oblivion when it came to the moons but that may just be holdovers in the NVGeck.