btw thanks inaki for your explanation
but to make things much clear putting my configuration file doesn't mean to
have a spoon-feed solution , i mentioned that am still new and before poting
my question i searched alot and read much more about avp module either on
kamailio site or voice-system tutorial but as am still in my first steps got
some diffculty to understand these issues
and finally i put my question for all people not for particular person and
who could help me i'd appreciate that