Keeping hard edges / smoothing groups after light bake


I am working on a mobile game but would like to know if its possible to keep hard edges / smoothing groups after baking lighting ? Right now when I bake lighting most of the meshes get smoothed out. We are not using any normals but it would be good if we could keep hard edges to preserve some detail and silhouette.

Lamp post lighting has not been baked and has hard edges.

Baked lighting with pretty much standard setup. Unfortunately most edges get lost and mesh gets smoothed out. Its quite possible its affected by lightmap resolution but maybe its possible to get hard edges without increasing lightmap resolution through the roof.

Hey, did you ever find a solution?