Was Tywin in communication with Mance Raider?

In ASOS, Tywin is asked openly at council what is to be done about both the Ironborn and the wildlings. At this point, the Iron Fleet controls much of the Stony Shore which borders the Westerlands and they also have a huge chunk of the North. You’d think that Tywin would be rather irate about that, but he brushes off the concerns of others and then says that Mance Raider might even make a good ally.

If you think about it, it’s classic Tywin. The North hates the Lannisters and the Ironborn are a nuisance to deal with. Rather than to fight them, why not invite the wildlings (who are used to operating in eternal winter) to pass over the wall and displace them all? The Iron Born will not hold the North in winter, the Northern lords will be frozen in their castles and without armies following the war, and the winter-hardy wildlings will grab up land left and right. You notice that Mance seems quite sure that he can succeed once he’s past the Watch. My theory is that he and Tywin had discreetly corresponded and that Mance was coordinating with him. Tywin obviously dies and Stannis changes things, but I think they may have been talking in the beginning.

Thoughts?