At some point, he'll have to say what he's going to do.
Avoiding the question on the basis of "the Poles and the Czechs haven't ratified yet" is missing the point, since they are going to ratify it soon, let's be totally honest. Eventually the public will get tired of hearing it, and want some principle.
However, if he doesn't want Lisbon, something to do now, as I suggested several days back, is to say he will hold an in/out referendum on EU membership if Lisbon is ratified.
Not only will that get the Eurocrats worrying (and possibly trying to stop ratification, who knows?), but it would probably be the only referendum he could hold post-Lisbon - Lisbon is self-amending so no more referendums on transfer of powers, it's not like the EU will allow a referendum on new opt-outs/transfers of power back to Westminister (or would self-amend them away anyway), and would probably give him an awful lot more support.
Free trade with Europe is the British way, political union is not. We've been independent since 1066 for a good reason - we like to be ruled by ourselves.