Sets all meshes in this object to use the specified image as a normal map. You can set a normal map for a single mesh by using SetObjectMeshNormalMap. The normal map will be placed in texture stage 2, overwriting anything that is already there and will have a shader generated that combines it with any dynamic lighting, to correctly light the object. If you are setting your own shader with SetObjectShader then your shader will have to make use of the normal map itself as AGK will not modify your shader in this way.
The normal map will use the second set of UV coordinates, if available, otherwise it will use the same UV coordinates as the base texture. If there is also an image in texture stage 1 (such as a light map) then the normal map will always use the base UVs.
SetObjectNormalMap( objID, imageID )