Creating a scene with a light sensor?

I have a problem - I want to turn on various lights around the house using an external light sensor> Ok thats easy you may think, BUT I only want to turn on some lights at about 20% brightness...eg a scene. Big question. How do you do that? the light sensor only turns on channels doesnt it?
then to confues it more - say I come home at night, the scene is on, few lights on here and there at the dimmed setting...how do I turn them all off? ie prevent the sensor from continuing to create that scene. be glad of any pointers.

 

Hope you have a key input such as NEO or Saturn,
Then make a scene on that key input and assign a trigger control group and action selector (255). Also create another all off scene (groups attached to first scene) and assign a action selector (000).
Then go the light level sensor and change the application to trigger control and select the trigger control group on "Light On/Off".
Then set your light level and test.

Ranil Roshan