Any agreement between Washington and Paris, as well as London, would also need approval from other Security Council members such as Russia, buy-in from Israel, Lebanon and Hizbollah, and the acquiescence of Syria.
Hizbollah is a militia. It's not a state, it's not treated like a state, and it doesn't have negotiating power. I suppose ever since the UN let Arafat carry a pistol onto the floor of the General Assembly, and created a special status for the PLO, this line - like much of the UN's vision - has been a little blurry. Still, when there's an existing resolution, 1559, calling for the dismantlement of this militia, saying that a Security Council resolution has to go to Bint Jubeil or Baalbek for approval is making some rather astonishing leaps.
So too for Syria. Syria's border with Lebanon may have to be policed for missile-smuggling, but that hardly requires Syria's approval. Syria's not an active belligerent in this war, and arming Hezbollah has got them the only leverage they have. What their approval is needed for is unclear, since they're one of the parties being policed.
It may be preferred to have Syria's cooperation on any deal. It might be desired that Hezbollah willingly line up, like so many Confederate soldiers at Appomattox, and hand in their guns on the way back to their jobs. But to say that either of these things is required in order to pass a UN resolution is giving malignant tumors (oops, sorry, Fidel) a little too much say in the operation.