Pakistan is an enemy, as Spencer Ackerman says, and we've got to deal with it on those terms. Treating it as a wayward friend who needs to be bribed to deal with problems just gets Pakistan keeping the problems in play so that the bribe situation will stay intact.
What Pakistani military officials always think about is conflict with India. (I'm sure they like being bribed too, but as far as actual foreign policy goes, it's India.) They've fought three major wars with India. They like China because it's a powerful counterweight to India. Insofar as they like us, it's as a source of stuff they can use against India, and they just play us for more stuff.
So the kind of thing we'd need to do to get them to do what we want is threaten to strengthen India's position relative to them. I'm not sure exatly what one does here, but I'm thinking of something like regularly updating India on what our spy satellites tell us about what's going on in Pakistan, including precise locations for all their major military hardware.