[Freeswitch-users] A-leg hangup cause is blank

[Emrah]

Hi all,

To be simple, I am trying to play around with hangup causes and see what I get in my environment. 
I must have a pretty shy set up because FS never discloses any hangup cause… It's continuously blank.
This is what I have before my bridge action:
<action application="set" data="api_hangup_hook=system /root/hangup_cause.sh ${hangup_cause} ${hangup_cause_q850}" />

My shell script just stores the hangup_cause I get in a file.

Ideally, I am trying to achieve the following:

1. User a calls user b; user a hangs up before user b picks up; I get a hangup_cause that is relevant and I can notify user b of a missed call.
2. User a calls user b; call goes to Voicemail; user a hangs up without recording a message; I get a hangup_cause that is relevant and I can notify user b of a missed call.

And so on and so forth.

With Asterisk, I would get channel statuses like NOANSWER, CHANUNAVAIL, CANCEL… and could act upon them. 
How do I get my FS to talk to me and give me some hangup_cause for my a-leg?

Thanks a bunch for all your help,
Emrah