Thank you for your quick response.
What I actually try to do is an overhead of Boeing 737 for a simulator. I have Prepar3D, iFly-373ng, FSUIPC (registered) and iFly2Fsuipc.
I want now control the lights of my overhead with 3 Phidget 1032 boards (http://www.phidgets.com/products.php?product_id=1032).
I started to create my own program to interface FSUIPC and Phidget : I can control the Phidget and thus the lights, but I can't have access to the information of the lights in the FSUIPC.
I tried to use the FSUIPC SDK but I'm not good enough to use it.
Is there any other solution ? Or