ViewerX is capable to establish UltraVNC Repeater Type I and Type II connections. The source code below shows how Type II connection can be established.

viewerX.ProxyType = ConnectionProxyType.VPT_ULTRA_REPEATER;
//IP or hostname of the computer with UltraVNC Repeater
viewerX.ProxyIP = "repeater.uvnc.com";
//default port value for UltraVNC Repeater
viewerX.ProxyPort = 5901;
//connection ID for UltraVNC Repeater Type II connections
viewerX.HostIP = "ID:1234";
//VNC server port
viewerX.Port = 5900;