Volume light color

I'm using a color gui element to allow the user to change the color of a volume light in my mission. it works fine except that the alpha is way up. I need to change the value of the 4th digit in the color.

echo(vlight.FootColour); works

Is there a way to access the alpha of the light - or any color for that matter? I thought the r, g, b, and alpha values would be accessible.

here is what I've tried unsuccessfully (vlight is the name of my light)

echo(vlight.FootColour.alpha);
echo(vlight.FootColour.k);
echo(vlight.FootColour.z);