Hi,
Are you saying CuteChat4 or v3?
You can use CuteChat.ChatWebUtility.HasReadyAgents() to detemine whether the agents is Online.
You can try to modify the Support-Image-Button.js.aspx or the Support-Visitor-monitor-crossdomain.js.aspx to fit you need.
It's the most easy way to pass your data by cookie.
But the browser will reject the cookie or do not send the cookie when the website using cross domain resources.
Maybe I am not understand what you want exactly . Please reply me if I am wrong.
Regards , Terry .