I think the procedure will be exactly the same as for FSX, with the same problems and solutions.
I have't tried their sceneries though... these might not work at all, since they are in FS9 format and P3D doesn't support that format at all anymore.
For the traffic however, it should be fine, but you'll need to convert the flightplans to FSX format first, else all of your native traffic will dissappear (because the WOAI and MAIW flightplans are in FS9 format).