Multiple Questions Sun/Moon light

Ok, so I have been reading some of the Mission Editor topic on TDN and found something that I think is what I am looking for but have some questions.
The Sun datablock topic talks about creating a new sun however, it didn't mention where to do this. So where would I create the new sun data? Also, the idea of this is nice, but what I really wanted is a moon. So I am assuming that I would just create the new sun as you would normally, but change the lighting it gives off.

EDIT: Another Question, but on percepitation. Was trying to add rain and managed everything in TDN's article up to the part about adding

Quote:
new Precipitation(rain) {
position = "0 0 0"; //Doesn't matter where it goes
rotation = "1 0 0 0"; //Doesn't matter either

...etc. to your mission file. So I was reading about some of the mission files and theres .ter, .mis, and .ml. Now this is where i'm lost. Is one of these the place I would need to put this? And how would you add it in? You can't open ter and ml files like a cs.