Help with text-on-mask-path - not working correctly in 3D space

I need text to animate around a cicular mask path so I have

1) made text

2) made path

3) made laye 3D and rotated layer 90 degrees to "flat" in 3D space

4) align text perpendicular to path

5) enable per 3D character rotation

6) rotate next 90 degrees back to vertical

So far so good; the text animates round the circle facing outwards, exactly as intended.

The issue is, I need the text to vanish at the far side of this circle. ie do the same thing it would do if you used CC cylinder or CC sphere and set the render mode to "outside only", as though the text is no longer visible around the far side of said cylinder/sphere (despite the cylinder/sphere being invisible).

However, I cannot achieve this - the text is always visible even when on the far side of the circle. This is confusing as even when I add an object at the correct position in 3D space that should mask the object, the text visibility pays no heed to the order of things in 3D space, only the layer order in comp view. You can see in the images that the text is still visible when at the far side of the mask path. (FYI I am using the 'first margin' property to animate the text along the path). This is despite there being a solid in 3D space at the centre of the mask path on the Z axis that should be obscuring the text when it is at the far side of the mask path circle.

I really need a solution to this; I cannot use CC cylinder or CC sphere as I need my text to be canted and do various other things that are not possible with these effects.

Thanks in advance for any help!