You shouldn't have to remove the speedo cluster to take off the headlight assembly, just the bikini fairing. This just unscrews with four hex screws, two either side of the speedo, from the inside of the fairing. You have to unplug the speedo (which wipes your clock and trip meter) but not remove it. The two nuts Ungeheuer mentioned, on the lower tripple, need to be losened and you can then wiggle the headlight off the mounting pins at the top. You then need to unplug all the electrics but after that I can't help you, as I never dismantled the assembly itself to get at the plastic surround.
if you are going to paint it, you might want to remove the speedo anyway
![waytogo](http://ducatimonsterforum.org/Smileys/classic/waytogo.gif)