You can either download The Alternative Scenario Set-up Mod or The Before the Conquest mod (for both see my signature). It makes use of the three 'extra' traits that came with DV.
Or if you don't like those mods, just download my minimod, which just adds three extra traits, from
here.
EDIT
I see you already found that one
If you want to mod in triats yourself, you can either re-use the existing ones and or use the three extra ones.
To give the traits a new name you need to edit :
Crusader Kings/config/traits.csv or Crusader Kings/config/deus_vult.csv
You can edit the attributes of the traits in :
Crusader Kings/db/traits.txt
You can edit the trait-icon in :
Crusader Kings/gfx/interface/traits.bmp
What kind of traits do you want to add to the game ?