You are able to make stunning attacks with special monk weapons.
Paizo Peripheral
This content is from Paizo, however it is not part of the Pathfinder Core Rules.
See here for details.
Prerequisites: Stunning Fist.
Benefit: You may use Stunning Fist when making melee attacks with special monk weapons as well as when making unarmed attacks.
Normal: You can only use
Stunning Fist when making an attack with an unarmed strike.
