[Captain Kwok]

Add the constant for your new trait as you've already done. Then copy one of the [EmpireName]_Setup_Script.txt files and rename it Narm_Setup_Script.txt. You'll see a function in that file that chooses the racial traits for that empire. Replace one of them with your new trait constant - in this case you'd want it to be added first. Open the Narn_Setup_Script file with the Script Parser and hit compile. It will make Narm_Setup_Script.csf, which you can then place in your Narn empire folder. If the game picks the Narn as an AI race, it will choose your trait.