maxscript vray fog color

Hi Guys,

I am having trouble making a material plugin script work that changes the fog color of a v-ray material.

I am trying to use this:-

delegate.refraction_fogColor = color 255 0 0

This should make the fog color completely red, but it has no effect. I seem to be able to change the reflection, refraction, IOR etc using the method.

Any ideas?