Go to this folder :

C:\Users\PC\AppData\Roaming\Command & Conquer 3 Tiberium Wars\Profiles\YOUR USERNAME\IDB

Open this file for GDI : 000_GDI_Internal_MemosIDB and you have to add :

421_TripodCaptured = 1
after Alien Origins

For NOD : 009_Nod_WeaponryIDBand and you have to add :

311_Commando = 1
after Stealth Tank