P2P signaling server (PeerServer) only forwards messages from sender to specific receiver. It can be easily replaced with your own implementation. However, conference server is more complex. It has a lot of components (agents). One of them is called portal, which handles signaling messages between clients and conference server. It also has some other functions, such as dispatching messages to internal components. As portal is a part of conference server, it can not be customized at this time.