Applying decals to geometry

Hi all,
I apologize for bothering everyone, but I’m having issues with applying decals on a body.
So I’ve been following this tutorial:

All seems to be going great until the last few steps.
I define the material (I don’t understand this step)…then I define the 2 textures (full body livery and 1 logo)…I put both of them as “clip”…now the strange bit. When I render my full body livery doesn’t appear…the logo appears in the right position and also as if I put the logo on the entire body.

Any ideas what I could be doing wrong?

I can’t really share at this moment, so I know it’s hard for you guys to guess. But any ideas and I’ll try them!

I didnt watch the tutorial, so I cant comment on the procedure used, but its for a very old build. Its over 3 years old…
Since it seems like you are new with blender, might I suggest learning Cycles and not BI.
You really need to post up a blend file so we can help.
http://www.pasteall.org/blend/

Hello once again.
Thank you for you help. I’ve managed to sort it!
Now I’m having another problem.

In the UV Editing window I can paint with the brush and get a full cover. But when I paint in the Default window with the same settings as in the UV I get a grainy finish (image below) and can’t cover up the grains.

Any ideas how to sort it and what the cause is?
It wasn’t doing it yesterday and suddenly started doing it.


EDIT:
So I’ve found out it’s happening because I have the mirror modifier turned on and the merge limit was too low.

Now can someone explain to the newbie what the merge limit is/does/mean?
And how do I apply the mirror? It shows in the default window, but not in the UV or renders!