On the Velocity website, it is under specials. You can either get a Circle Pacific fare (which I did for my last trip SYD - LAX - NRT - SIN - SYD) with VA/SQ or an RTW trip.
You can't book it on line & forget about calling VA or SQ. VA transferred me to at least 5 people who had no idea. SQ's idea of a Circle Pacific was SYD - SIN - NRT - LAX - NRT - SIN - SYD.
The best way to get one is via a TA - go to one that specialises in RTW travel. If possible take a copy of the relevant page & the T & C with you.
I booked my Circle Pacific fare via Best Flights by calling their RTW hotline but they've had a change of business model since I booked. They are also quite hefty with their change fees.
Work out via the airline websites or other planners the flights you want first. The specials page on the website mentioned above will give you a sample routing. For RTW especially, it is limited to VA & their limited partner airlines due to their lack of an alliance.