Hi, I'm new to 3CX but I managed to get a SIP trunk online. Incoming calls are working. However, when I try to call external numbers via the SIP trunk it doens't work. I call my SIP trunk provider and he told me that in the outgoing SIP header I need to a P-ASSERTED-Identity part where I need the put the DID I got from them. Can anyone tell me how I should do this? I know I have to change something with the parameter on the SIP trunk outbound parameters. Anyone can help me with this? 3CX V10 Intertel is the SIP provider Used the Generic Provider template I use the Softphone to test.