Wood trimsheet edges are dark - I need them to be light

Hello everyone,

I have created a wood trimsheet to texture most of my wooden elements in this scene. I created a high poly sculpt in Zbrush and then baked it onto a flat 2k plane in SP. 

The idea is that the light should be reflected by the sculpted edges, and in turn they should be lighter. However, the result I'm getting is that they are darker and don't reflect any light. 

I guess this is logical considering that high poly wood beams are aligned on top of one another, and the sculpted edges fall into the dark area. But this is not what I am looking for.

If you have an idea, could you provide me with a solution to get my edges ligther instead of darker?

Thanks in advance!