MC Xbox 360 villager breeding problems?

I brought 2 villagers, a farmer and a librarian, to a new (empty) village to restart it, but they won't breed. There are enough doors for 2.5 more villagers, i have traded with both of the villagers 3-4 times, sometimes at the same time, and i've even locked them in a 4-3 area together for a cupl minecraft days. Its been ~10 minecraft days and they don't do anything besides 'socialize'. I have watched them for 1 straight minecraft day, been in their general area for several minecraft days, and been half the map away for several minecraft days. Its in xbox 360 superflat survival. What's the problem?