Kerf width on Multicam 1000 Plasma

Does anyone know how to set the kerf width so it is loaded with the material library?

I can see a parameter in the material library editor called g_diameter which seems to marry up with the kerf settings, but its never loaded when selecting a new material on the machine. I also note that anything under the Params 2D -> Settings menu never gets loaded either.

Initially I thought the EZGcode Creator would compensate for Kerf width, but every time I do a cut without setting the kerf width it is out by exactly the kerf width. What am I missing here?