I tried MCEdit to copy very large build and I exported it to .shematic and imported it into a new map (1.2) but the build is not complete. There is some part that are missing. I tried to do it with smaller selection and it look like to work but it's going to take long time to do it because I have a lot of big build to copy (few complete city).
Do you have any other way to do it? To copy very big build from 1.8 map to 1.2 map?