UltraVnc Single Click - II & III
UltraVnc SC II
UltraVnc SCII is the version that can be found with the Online creator.
SC II allow to make inverse connections, server connect to viewer, and repeater connections.
When a repeater (mode II) connection is used, both server and viewer initiate the connection so no port forwarding is needed.
See also
SC Step By Step by Donald Muir,
uvnc.com/addons/singleclick.html, and
Forum SC
To fully use SCII you need to understand how the repeater works.
Documentation about the repeater can be found
http://www.uvnc.com/addons/repeater.html
Check the info about mode II.
SC III (SSL)
SC III is a Single click version that make use of the repeater in mode (III).
SCIII require a repeater(SSL), a special viewer(SSL) or a Java(SSL) viewer.
Also see Forum SCIII
Java VncViewer (SSL)
How to test
Server -> add new client