Enchant Creature Activated Abilities

[Toast]

I was playing in a kamigawa block draft when this rules situation arised....I had a "Iwamori of the Open Fist" (a 5/5 trampler) that would have dealt lethal damage during my turn. On my opponent's previous turn he had played "Cage of Hands" on my Iwamori (enchanted creature can't attack or block. and 1W: Return Cage of Hands to its owner's hand.). On my turn I had enough mana to pay the return ability so I tapped 1W and attempted to return the enchantment to my opponent's hand. My opponent claimed that i could not do this because it was his creature enchantment. I contested that since he had cast the card on my permenant it gave my creature the ability to return the enchantment to its owner's hand. Who is right?

[Ephraim]

Your opponent is correct. An enchantment that grants an ability to a creature will read "Enchanted creature gains..." Iwamori didn't gain any abilities from the enchantment. The ability to return Cage of Hands to its owner's hand belongs to Cage of Hands itself and can only be activated by the controller of Cage of Hands.