Compiling JBoss Branch_4_2 with Ant 1.7.x [Was: [jboss-dev] Compiling JBoss Head with Java6]

Hi, I have many requests of people wanting to build the AS 4.2.2 (Branch_4_2) with Ant 1.7.0 and they claim it fails to build. I assume AS 5.x already builds with Ant 1.7. Someone remembers which were the changes that had to be made? In the meanwhile I will ask what the problems were and try some experiments myself, but if you already know the answer you can save me the trouble ;-) Regards to all, Fernando