Ryzom

First, thanks for your reading.
I found that it don't use ULight to create the light in ryzom. And it use Scene->enableLightingSystem() and Scene->setSun***() .Why?

Because I found that the light can't change my shape added into the scene, But the light can change my landscape.

So, I want to the method that what and how to set the ig?

Another question is :
If I want to add a point light, Which method should I use? just use the ULight to create the light?
I found a method UPointLight and CPointLight, But I don't know how to use it.