First, get valid license key and Enterprise Version from their download page (use deb package), just click downloads, try it and download.
In case type
Edit /etc/vnc/config and add
to set encrypted connection and allow users. Then start it via shell by typing vncserver and connect from another client (which has the enterprise vncviewer available).
In X configure the vncserver to accept only VNC password if you prefer this authentication method.
Then do the startup thingy
-c "/usr/bin/vncserver -geometry 1600x1200 -depth 24 > /tmp/vncserver.log 2>&1 &" &
and reboot. Connect to