Ok, I'm assuming that the case badge spot you have on the door is 25x25mm and that is where you are planning to put one in the future.
Best thing I can think of off hand is, and you will probably need to do some wire cutting and soldering, is get the hole drilled where the old case badge is. It will probably be easiest if you cut the wire on the EL badge in at about the 3" mark and solder a nice long set of 26 AWG (gauge) wires to it as we will be runnign some wire on this to make it work. Run the wire right down the middle and the across the bottom of the door to the hinge.
You can do a few things here. I would drill a small hole big enought to get two 26 AWG wires through and so that when you open the door it will not need to pull up much slack wire. Once you have the wires through, I would then solder the remaing 3" of the original badge lead wire (the one with the connector on it) to the the wires you just threaded through the hole. Have the inverter inside the chasis and drill a hole so you can feed the connector from it to the outside of the chasis on the front to connect it to the badge. That way when you want to take your front pannel off all you have to remember to do is un plug that inverter lead from the badge lead.
To hid the wires on the back side of your door, just go to the auto parts store and get some of the pimp @$$ gold trim or something to that effect to cover it up with.
