At this late stage and with the demand out there for business reward seats, it's a case of simply regularly checking (or setting up an alert on a site like expert flyer) and seeing if something becomes available. Individual legs can be done.
Almost immediately I got the confirmation email. It also showed up straight away in my Velocity dashboard on the credit card promotion page that I'd selected a benefit. If same for you, suggest you take a screenshot.
Similar question but booked via VA rewards. Arriving into Singapore on a morning flight. Any issues with booking a second VA rewards flight departing onwards to Australia either early morning next day (18 hours between) or the next day morning (+24 hours between)?