Add gradient ramp colours to vrayenvironment fog on spherical object (gizmo)?

[stevesideas]

I've selected a sphere as a gizmo for the vrayenvironmentfog and was hoping to be able to have falloff colours change via the gradientramp. So basically the outer edge of the fog gizmo is white, then as you move towards the centre of the fog it changes colour to whatever the gradientramp is set to.

Is this possible?

[hermit.crab]

Using a VRayDistanceTex to map the Gradient (plugged in the Fog Color tex slot) should work. Attaching a sample scene.