I'm doing this mod tomorrow but I dont have the black housing (had my bumper replaced) so I will use some epoxy to glue it from the inside.
Will try this wiring:
-ON with parking light
-Flash with brake light
-Flash with reverse (using a diode to not activate brake light when reverse is on, viceversa)
-Separate switch for constant ON
-Flash when door is open (not sure about this one)