1. Open Editor
2. Place a Missle Specialist (AT)
3. Place a enemy vehicle (such as Ifrit/Hunter/Strider ... depends what faction the (AT) is)
4. Preview
5. Change difficulty settings to Veteran/Elite or switch the AutoGuideAT command to disabled
6. Equip the Titan AT and lock on to the enemy vehicle
It now locks on and will be guided into the target as well.