UV islands mess up normals in exporters

I’ve been trying to export a model, actually a normal mapped game model, in several formats, and whenever I view the exported models with real time per pixel lighting I can see clear breaks in the lighting where uvs are split. This has nothing to do with the textures, I tried no textures and it was the same. It’s nothing to do with the model, that I can see, in blender it’s self.
The formats I tried to export to are obj and 3ds, which both have the same problem. I also have this problem with the crystal space exporter. I’ve also tried different “viewers”. Anyone familiar with this problem, or where I should look for to fix it? Clearly it’s getting incorrect normals somehow, I can see that in XNormal. so is there a proper way to export normals from blender?