You have to enter a parameter into a T2 shortcut...I think..It's been about 1 year since I've coded anything. I believe it's something like
C:\Dynamix\Tribes2\GameData\SierraUp.exe -mymod
enter the name of the folder your mod is in where it says mymod...If it doesn't work...yet again go to the site above...everyone there is a great help to anyone looking for info :D