Dell XPS 12 - Switch on Computer while lid is closed

I use my laptop as a normal desktop machine (with additional display and keyboard). Due to the fact that the computer is stored in a small slot below the desktop, I want to switch on the computer while the lid is completely closed. The new XPS 12 doesn't work that way, the lid must be lifted an inch or so. Any idea? Bios? Under power settings I can only determine what should happen when I close the lid, I found nothing to change the behave while turning on the computer.