You're using a melee attack power, but the creature that makes the attack isn't you. In order to qualify as an attack or attack power for an effect, you need to make an attack roll (Divine Challenge isn't an attack, and neither are damaging aura effects). In order to qualify for effects to damage rolls, you need to make a damage roll (static-damage attacks don't count unless otherwise specified). Claws of the Eagle and Commander's Strike do neither: the ally makes the attack and damage rolls, so you need to use effects that trigger on an ally's attack or damage roll. However, you are still using the power, since it is by your power that the ally makes the attack. Thus if something precludes you from activating that power, you still can't use it even though you're not making the attack and damage rolls.