[asterisk-r2] Called party hangup detection in R2

[Alejandro Burastero]

Hello all,   

        I am using an R2 from Telecom Argentina to send multiple automatic
20 seconds messages with .call files and extensions_custom.conf .  I want to
detect how many seconds the called party listens to the messages, but the
hangup is detected about 5 to 10 seconds later, so the CDR information is no
exact. Is this a configuration problem ?

Thank you

extensions_custom.conf
[llamada]
exten => s,1,Answer
exten => s,n,Wait(1)
exten => s,n,Playback(prueba)       
exten => s,n,Hangup