That's my understanding. To quote your quote "I create a prop with the old UV coordinates as UV coordinates (do'h) and the new UV coordinates as x,y positions." He specifically mentions a prop, and I've made a much simpler UV transform prop myself so I know the technique is sound. Also, odf said it, so it must be sound. :)

I've been searching for the prop I made, but all the discussion took place on the DAZ forum circa November 2010, and I can't find an archive of that anywhere.

odf's comment about uv coordinates versus xy coordinates ought to be a clue. I'll mull it over and see if my brain can get into gear.