Look in my mini thread. Did the same. You have to use brutal force with a tool cracking/smashing the white lens and remove all pieces by hand than just glue the other orange one to it to make it waterproof and that's it.
IDEA! Thanks very much. I thought about cutting the old one out around the base with a stanley knife but I thought that would let water in, so this is definitely the better idea. What did you use to crack it open?
probably a hammer
I know that seems the obvious answer, but actually, that plastic being the cone shape it is, it is actually pretty damn strong thing (much like how an egg is weak from the sides but strong at the top). Seeing as I don't have a vice I can see hitting it with hammer will have the effect of launching it across the room.