Irrlicht Engine

I create a scene using irrEdit. The scene has already been rendered with irredit and come with lightmaps. Afterwards,I load that .irr file, but when I added a lightnode in the scene, it seems there's no change on the screen. Object added later was not lighted.
What's the problem?Any one can help ...

thanks:)
i take a look through the link, the effect is perfect but i think it's a bit hard for me cause i don't know openGl actually..

hi, i got stuck with a fog problem.

i loaded a .irr house scene in, and i wanted to create fog in one of the rooms (bathroom, exactly..).
but since the house itself is a node, does this mean that i can only make the whole house foggy by calling setFog() ?
is there any methods that i can create fog ...

thanks:)
tried but still quite weird...
anyway i tried to add all the lighting in irrEdit and save as .irr file and load as a scene and it works fine.

thanks:)
I added
house_node->setMaterialFlag(video::EMF_NORMALIZE_NORMALS,true);
but still got the same problem..i guess the wall's normal is not right. but how to use MeshManipulator to change the nromal?
is it using
smgr->getMeshManipulator()->recalculateNormals((house_mesh),true); ?
I tried to ...

hi,
I loaded a room of .my3d format and try to light the room with a lighting node, but it seems that only the floor is lightened, the wall is all black.
I have adjusted the radius of the light and it doesn't work.

the code relevent is as follow

//code for a room
scene::IAnimatedMesh *house ...