I'm not sure if you are explaining yourself clearly now or not.
If I understand you correctly, you don't want to turn the lights on, but if a room is empty for a period of time, then you want the lights to be turned off automatically.
Almost every PIR motion sensor is already designed to handle this type of situation. In Vera you can open the device settings for the motion sensor and set this time-out to whatever you want (see attached image for example). Then when there is no motion in a room for that period of time an event will be triggered and you can assign this event to your Vera Scene, or a VoxCommando macro which turns off your lights. There is also an added benefit to doing this. If you set the timeout to a longer period then the batteries in your motion sensor will last longer, because it will need to wake up the radio less often in order to report motion/secure messages back to the Vera controller.