It really is quite simple once you get the hang of using the ANA availability tool so I suggest you start reading up on how to use that first. Finding routings using the Star Alliance timetable will also give you some ideas of other route options available to you.
You say you are pretty flexible with the routing but if you can also be flexible with your travel dates it will also make a big difference. The ICC were probably correct with their reply if you asked for a MAN-SIN-SYD on a certain date.