I hope someone familiar with Dodge replies to your question but I would look on the Dodge Charger forums and enthusiasts that post that type of performance modifications. I have also contacted the manufacturers of the aftermarket Xenon lights and got information directly from there websites or customer service for other car manufacturers that I have done modifications to.
I am an upfitter and "build" police chargers. To change the headlamp assembly as a whole - you have to remove the front nose (bumper cover and grille). My advice to you would be to find a body shop nearby and ask their techs to show you which fasteners to remove to accomplish this. Another idea would be to find a shop with Alldata and get them to print you out this procedure. It seems like a major task, but really isnt that bad once accomplished.