Larmar,
Heating the milk to 180 damages the proteins in the milk. Oddly, sometimes that is what you want to happen -- for example, when making yoghurt. But for the vast majority of cheese, you want the milk never to get anywhere near that hot. This is why ultrapasteurized milk is generally useless for making cheese. In fact, most people have to experiment with different brands of "regular pasteurized" milk to find one that works well for making cheese.
If you can find low temperature pasteurized milk, or even raw milk, you will get far better results -- or so I am told. I have not yet laid my hands on any such milk. However, that is about to change -- this week I am taking delivery of a couple of gallons of raw milk. It only cost $10/gallon ... !
Andy