Disarm skill - What all does it work on?

[Ashimar]

So i disarmed a drolvarg in DL earlier and it got me wondering, can you disarm
a named mob with an uber sword/staff/ect? im guessing no because when a expensive weapon suddenly gets dropped to the ground, anyones game to pick it up and keep it for themselves. I've tried to disarm mobs with semi-uber weapons and it hasnt worked yet.