A LightPlacement is an object that is part of the system.
Systems are just code that run once when a Set (what BC calls Systems) is loaded.
The code in a System definition could be run at any time (assuming a set is loaded of course).
Since a LightPlacement, just as a Ship are objects that are part of a system, they both have the AttachObject function, so you create a LightPlacement after the game has started, such as when you click on a button, set it to the location 0,0,0 (or where it is supposed to be on the ship), you configure the light of course, and then do pShip.AttachObject(pSpotLight) (or something similar of course!). Now the spotlight will always move when the ship moves, and turns when the ship turns (as if it's a fixed part of the ship).