There is no portable heavy weapon that can defeat an armored vehicle. If the missiles tubes presented in both core books (the Golan Arms HH-15 or the Merr-Sonn PLX-2M) are able to destroy a speeder bike or damage seriously a landspeeder or an airspeeder, they are barely able to scratch a lightly armored military vehicle. With a damage of 20 character-scale (2 vehicular-scale) plus 1 Breach, the missiles tubes just pass the Armor of an AT-ST : so, what is this weapon which is able to take down an AT-ST in that trailer?
https://www.youtube.com/watch?v=gsA0hpogJL4
Apparently, RPS-6 rocket launchers were successfully used in the Clone Wars against Heavy Missile Platform droid gunships on Onderon (see Star Wars the Clone Wars Saison Five episodes 2 to 5).
RPS-6 Rocket Launcher
Portable guided/unguided anti-vehicle weapon widely used in both camps during the Clone Wars.
Weapon Type/Model : Rocket Launcher/RPS-6.
Manufacturer : Merr-Sonn Munitions Inc.
Skill : Gunnery • Scale : Vehicular
Damage : 4 • Critical : 2 • Range : Long
Encumbrance : 6 • Hard Point : 3
Price/Rarity : 2,000 ®/5 (launcher cost).
Special : Blast 4 [Character scale], Breach 3, Cumbersome 3, Guided 3 [optional], Limited Ammo 6, Prepare 1.
Rocket Cost (rack of 6) : 6,000 ® (guided), 1,500 (unguided).