In order to keep it simple, just write your Mii/file name in Mario Kart Wii. Type in your name you use for Brawl.
Examples:
Mario Kart Wii
-----------------
Name: Mii/File Name
Friend Code:********
SSBB
----------------
Name: *Name you commonly use*
Friend Code:*********
Simple and effective.
Remember to keep on topic and chat about all things Wi-Fi
From your Admin,
SNG