[Serusers] USE XLOG

Hello, I am a student and i do a workplacement. So i must work on the VOIP, but ihave no experience in. I would like know thank to a log, when an user connect/disconnect his user ugent. I know that i must use xlog, but i'm lost for many reasons. The first : Idon't know variables i must use to do what i want. The second : I don't know where i must write the line in ser.cfg to have this log. The third : Where is the log generated by xlog, and if there isn't one, how i can create this log. The fourth : If i must write something in xlog.so, how open it. Because when i open it with VI or NANO there is only encrypted data. THX to help me. If you can answer on my mail : sylvain.nigen(a)legos.fr, because it's easier ton know if i have an answer than to search the answer on SER USER. THANKS