Bebelith rend armor

[Biggus]

Rend Armor (Ex) If a bebilith hits with both claw attacks, it pulls apart any armor worn by its foe. This attack deals 4d6+18 points of damage to the opponent’s armor.

Do you subtract the armor's hardness from the damage done by the rend armor ability?

[Venger]

Yep. And remember to add +2 to the hardness and 10 to the hp for each +1 enhancement on the armor.