Dont get led astray and I put this to you,

If you inport a vehicle into Aus, you must modify it to comply with Aust standards.
Therefore just because it came with factory equipment means jack if it doesnt meets our requirements.

All the bikes over here come with a centered numberplate as standard.

Harley make everything for the Yank market which have different rules and just because its sold over here dosent make it legal to use over here.
And its not cost effective to produce an accessories book that only contains items that comply with each region.

I have a mate at QLD transport who told me that they will never approve side mount number plates or even curved holders on the rear because its a camera thing. It must be completely visible from a 45 deg. angle so the cameras can see it. In QLD anyway.

the plate needs to viewed from 45 degrees on every angle when looked at from behind and not protrude 150mm.

Agree with all of the above, however I did see a breakout with side mount attached to the rear blinker housing.

This would pass here in Oz with a viewing access of 45 deg.

This guy purchased it in the US. Heartland was the brand

Im wordering if there is such a thing for a softail