If you will need to pass information to signaling server you can use custom properties for IMWebRTC object via IMProps interface, for example:
m_objWebRTC.PropsSet("remote.custom_property", "custom_value")
//pay attention, property will be passed to signaling server only with 'remote.' prefix.
This value will be available on the signaling server and also for all peers which are going to be connected to the current peer (m_objWebRTC object)
Now go the signaling server source code, we run it under debug so we could set the breakpoint and check the properties list
node --inspect server.js
Ok, let's suppose that we will send the data via remote.property, but how we can receive the information back from signalings server to peer?
It's also possible, via 'servermessage' handler, you can add the following code to signaling server
client.emit('servermessage', {payload: 'your_message_here', from:'signaling server'});
As soon as you will connect to the signaling server your IMWebRTC object will receive an Event from signaling server with your message (JSON string) as the parameter.