The Shengen is not a treaty just an agreement and unfortunately as far as Im aware EU rules supercede it, just like everything else the EU gets its claws into.
Theres no way the EU would have allowed anything like this to get in the way of the formation of THe EUCCP.
Without the EU then Shengen would have been far more preferable and i'm sure a decent case could have been made for us to have been included, but alas its far too late now, the EU has see to that.
/// The Schengen Area operates very much like a single state for international travel with border controls for those travelling in and out of the area, but with no internal border controls.///
Much as I regret it I must agree with Gromit on this one.
So of all the countries in the EU they'd come here we all agree on that but why? could it be that we are the only sucker in the EU that gives out free money?