Since I cannot reply on my topic:
viewtopic.php?f=1&t=88457
( I receive this when I try to reply: s12.postimg.org/5pblv4099/Scherm … _01_36.png 
)
Here is my response for david55,
we are using SIP as channel technology.
Thanks in advance.
I don’t understand why your access to the forum is broken.
If you are using sip, enable SIP debugging (sip set debug on) and see if there is a Diversion header containing the information you want. If so, I believe that the method I described should work, give or take spelling errors.
If not, look to see if the information is there in any form. It may be possible to recover it using direct access to SIP headers.