Our gateway supports loading a OpenVPN Client Certificate to connect to your OpenVPN server or router. By default it will allow routing to the box to do configuration changes but you can optionally tell the gateway to route all its voice services over the VPN also.
Click on Basic > Network
Scroll down to the VPN Section
Click on Enable and press Save
Upload your OpenVPN Client Certificate and press the Upload button.
The file name must be named client.ovpn
You will get a pop up saying the upload was Successful
By default the gateway will not route voice traffic out the VPN. You can force the voice traffic to use the VPN by Enabling Voice Traffic here.