The number format for DID and Caller ID must be in E164 (+32,+33, etc..)
Note : If you plan to create multiple trunks that will be registered to the same IP and Port on your IPBX this could lead to stability problems. Please make sure to use separate IP:port for each trunk or contact us in order to create separate accounts for each trunk if you are unable to do this on your IPBX.
In the end your callflow should look like this :