Default [Q] [help] Xperia Acro HD SO-03D jb update

Hey guys! I got this device from my cousin as a present and ive been doing some research and found out that it can be upgraded to jb as well. I know that this is the same as the Acro S. I saw some posts here on XDA saying they succeeded on upgrading it to jellybean. That's why im here because i really dont know how to do it. Can someone give me a step by step guide with the files needed or just link me to a thread? They said they lost their IMEI though after upgrading it any way to prevent that?