As I've stated before on this forum, I don't think the administration wants to acknowledge this because they fear that if Syria thought we were going to come after them, they might be further scattered amongst terrorist-sponsoring nations. As it is, our intelligence agencies are undoubtedly trying to learn their exact location and what they consist of so that we have an opportunity to safely destroy them.
The UN put out a report the summer of 04 stating that the WMD went to Syria and from there some have made it to Turkey and Holland. Sounds like Europe is gonna have some "fun" in the future.
I would imagine the Israelis, for whom the weapons are also a threat in the hands of the Syrians, know pretty much where they are. They've always had pretty good HUMINT capabilities in the region.