Light House and see shore

Hi, i’m working on this project form the book Blender Basics 4th edition, but i’m giving it a personal touch, so i’m experimenting a little bit, the problem is, i’m trying to give give it the fog effect they use in the book but since i’m using a dark night as my world settings, the “fog” effect is pretty weird, it just looks darker, but not like if there where mist in the scene, i really don’t like the idea of doing what they do in the book, and switch to a kind of daily sky, and since i don’t know who to use the smoke effect i’m stuck, ¿any suggestion? .

For those of you than find i difficult to understand my explanation (as i my English grammar construction may be a little sucky), i’ll provide some screenshot.

http://img69.imageshack.us/img69/1849/ligthhouseandseeshore.png
This is what i have, i the “fog” look weird, don’t know but i don’t think it looks anything like fog.

You need to tell us what kind of look you are after. Because, basically fog at night will be all black! Unless there is some light source like city light or moon light to make the mist visible. In your case the image might look like this one.

well, i actually have 2 light sources, they are withe and are behind the camera, but the mist color is black 'cause to the horizon color is black, so i would like to know if there is other way to set the color of the mist to white other than to switch horizon color to withe (witch would affect the night scene).

EDIT:
I got the effect i was looking for (kind of) i applied a cloud texture to the world and all the scene got this white mist that covers the hole scene.

http://img52.imageshack.us/img52/5616/unledkcs.png

The problem is, i wasn’t aiming for that when i applied the texture, i actually wanted some clouds up in the sky, ¿ what can i do to achieve that ? ( i tried using a Y offset but i didn’t work at all ).