Not sure if anyone replied however the PBX connected information must show your external IP not internal. I'd suggest you setup a DYNDNS account and place that infomation within the sip_general_additional.conf. The lines you'll add to the sip_general_additional.conf file are:

externhost=myname.dyndns.com (myname=your domain name)
externrefresh=120
localnet=192.168.1.xxx/255.255.255.0 (your local network IP)