Yes the current beta source code is in the current applet. But I'm currently working on a cleaner GPL version (including javadoc checkstyle etc ...) that will be available at sourceforge soon.
Regarding passing the SID automatically to the Viewer should be possible. But the password ...
If you are interested in a VNC solution that goes through Firewalls, proxies, NAT ... with out any particular setup needed try this : http://www.vncproxy.com