4PSA Voipnow Professional seems to be clone of AsterisksNow or enhanced version of Kamailio. I've extensively worked on Linux Administration. I've implemented Asterisk on CentOS, used AsteriskNow and have skills on HTML/CSS. I'll be able to fulfill your requirement. Without any upfront, I can provide you a demo of Re-Skin using the Free Version of 4PSA Voipnow Professional.