The Tory problem is that there is little agreement on what, precisely, should be done. The EU offers no reverse mechanism. Hague is implying the Judge Dredd approach to problem-solving ("if I can't find a way, I'll make one") yet given his problems over the EPP withdrawal, would the party trust him? From my inquiries, there points are clear.
1) A great number of Tories view resolving the Europe question as a fundamental, almost existential battle.
2) An equal number consider the issue toxic, and don't want to revive the monster they believe sunk Hague in 01
3) Crucially, both sides realise now is not the time to fight. Unlike Maastricht, there is no chance of a parliamentary veto for the Lisbon Treaty. The Lib Dems are not on side, and even if they were Brown's majority of 67 is enough.
Brown plans 15 parliamentary days over the Lisbon Treaty, ie five weeks including recess, and his aim will be to push the Tories over this line that Hague and Cameron are carefully defending. He'll pray for a Major-style split. And my hunch is that he will be disappointed.