I think I have solved part of the problem a little bit by increasing the brigthness of the light map.
So far I have only applied a new light map texture to one building but it seems to work, I don't know if this solution could affect any other render settings.
The 2 drawbacks to this solution are:
1 the lightmap can start to show a bit early.
2 the lightmaps are not guides which light up the normal building textures anymore, but basically independent textures by themslves which swap the normal building texture, and reflections during night time.
This requires a lot of work to make the light map textures, which could take a long time but I think it might be worth it.
On the following pictures all the windows are black on the buildings texture, the reflec-map goes exactly on top of the windows, during the night the textures on the windows almost swap with pictures of real windows taken from wikicommons , some lightning effects were created by blending alpha channel and the normal building texture.