I used this method and have the trees showing in P3Dv6, the only P3D version I have installed is v6, so far I have all my Orbx sceneries working flawless(installed them using the registry trick posted elsewhere), with the exception of some trees at some(not all) airports.Hence my sugestion to Orbx start the updates with the trees. I woudn't mind paying a price for that.
BTW, I have all my 3rd party add-ons installed and working in P3Dv6 except the ifly jets and QW787