VrayMtlWrapper not transparent

[ahmadkouti]

Hi.
I've used the VrayMtlWrapper in 3ds max 2015 , but for some reason, I can't get it to work now in 3ds max 2107.
all set up correctly I should think, but the RGB is not transparent .
Look at this image and file. A very simple scene with a dome light.

[svetlozar.draganov]

Everything works fine here, the ground plane with Wrapper materials renders the black environment color.
The light color behind the sphere is the visible dome-light, make the dome-light invisible and you'll see that everything works as expected.