With my conversion table it's actually not that difficult anymore:
Armor class: 4 (Plate Armor 3+1 for siz &con)
Claw 8 (weapon class 2)
Bite 8 (weapon class 3)
STR 8, CON 7
Numbers: 1 or 2
On Nirdday and its mirror world Yaddrin, the Panzer Bears are only known as weaponized polar bears, used by the Northern Elves in punishment expeditions. They are in all probability of extra-terrestrial or even extra-planar origin. Their most notable difference with normal polar bears is their high intelligence, and speech. Their armor was forged by the elves who bound them, and the armor also serves as a kind of soul prison - forcing the bears to attack ferociously if the elves give the attack commands. Sometimes the panzer bears are used as sentries to protect polar bases or gates to other worlds, and then given magickal standing orders. A panzer bear that is freed from its helmet may either turn out thankful, or go stark raving mad and attack.
With thanks to JB and Phillip Pulmann for the basic crazy idea.