Yes, absolutely... first in the RaiderSoft control panel you want to be sure to specify the referrer URL, so that the chat app will only load if it was accessed from that location.
While you are there set the custom authentication script URL.
Then upload the custom authentication script (the attached file in this thread). In your page that loads the chat applet just specify the params above and you got it.
The way I do it is with a link to rchat.php, which verifies that the user is a valid user, and if so it gives them the rchat.tmpl file which has the applet code embedded in it.
Let me know if that helps. I can send you the files if you'd like.