Shadow strength doesn't matter in beast lightmapping?

I have a strange situation. I've already created a new empty scene to test it to make sure isn't any previous setup problem.

A single box and plane, a directional light with hard shadows, and shadows strength at 0.3, all marked as static. After the bake, the far lightmap only shows a dark shadow (with strenght 1), as I get near the shadow, it is replaced by the realtime shadows, brigher (0.3). It doesn't matter with shadow strenght for the lightmap?

I've already tried to increase ambient lighting. But this affects the hole scene, including the light areas. I JUST want to soften the shadows, any one has any clue on this?

I'm sure that I'm missing something obvious here...