I think we need to clarify this talk of Taliban being the Pakistan Army's assets. If you listen to high level US/NATO officials speak, you will see that Pakistan does not control these terrorist groups or their leaders, & they operate on their own, on their own will. These terrorists are mercenaries, who don't have any loyalties to anyone, not the US, not Pakistan, not anyone. They have shifting loyalties, & have been used by different "parties" over the years. They don't have any loyalty to religion either: they are ready to kill innocent Muslims, people praying in mosques, on Ramazan & Eid. So these people are mercenaries, not saviors of Islam, not resistance forces against the US, not anything; & don't have loyalty to anything except power: that's the truth.
The US/NATO Forces need to collaborate with Pakistan, not make Pakistan center stage, pushing all the Afghan terror into Pakistan. The US/NATO Forces have failed to do any of that, & their lack of trust in Pakistan is harmful to everyone in the region, going as far as Russia.
Okay, take it like this - This is a covert war. There will be no hardcore proof or admission by any party supporting any particular terrorist group involved. But you see, the Pakistani Army has been going after all the terrorists in the area (Swat + FATA), but has flatly refused to go offensive on the Haqqani's.
Army's Assets:
What is it that makes the Haqqani group so holy? It is known to all that the Haqqani group has been collaborating with the TTP to raid the supplies and attack the Armies inside, as well as outside Pakistan. They have been collaborating for quite a while already, and only recently the Haqqani group is said to have been distancing itself from the TTP for the reason that the TTP attacks civilians. Well, it has been attacking civilians for eons. Haqqani group came to see it just now? In the international journals, the Haqqani group is called the darling of the ISI.
Infiltration from Afghanistan:
Also, the call you are making, that they are infiltrating from Afghanistan, is very similar to numerous calls made by the Afghans and the NATO that the terrorists are infiltrating from Pakistan area and the PA is not doing anything. It happened for a long time, followed by a lot of bitter confrontations between the Pakistani Army and the NATO/American forces. Now the tables are turned. The Terrorists run into Pakistan, but not vice versa.
Collaboration with (Read: Contribution of) the Pakistani Army:
I have cited a particular incident many times in this forum, so I won't anymore over here... but just know what happened: The American forces went after the terrorists. The terrorists ran into Pakistan - through a border checkpost manned by the Pakistani Army. Shots were exchanged. No terrorists died, or so was reported. But heard of some casualties on Pakistani side. Entire group of the terrorists vanished into Pakistan.
Next day, confrontations. Oil tankers lighted. Supplies halted.
The terrorists raiding the Pakistani side from Afghanistan is a very recent phenomenon. Earlier it was the other way round. But it does not mean that the Americans or the NATO is facilitating that infiltration. It simply means that it is tougher for them (the terrorists) to be in Afghanistan now, and Pakistan appears much safer for them to conduct their business.
It is KPK, that had been turned into a massive terrorist factory in the name of Jihad, and no one bothered to dismantle it after the job was done. Besides, it is still too lucrative to dismantle it anyway.