The easiest way to exclude an entity from the lightmapper is to make it dynamic then set isimmobile=yes on the properties.
Black Ice Mod has a bunch of dynamic entity shaders so you can ensure the entity doesn't look completely out of place with the rest of your lighting but it will no longer cast or receive shadows. It should be fine on smaller objects like a lamp though.
You can't turn on lightmapping with doors for the same reason i.e. they need to be dynamic for animations. We include a shader for doors in Black Ice also.
