I am pretty sure I asked about this awhile back. The Vision control does not have a z-scale (color) palette (unlike the intensity graph which does). So you have to roll your own. If you see the attached VI, it shows an array that simulates a color bar. You would have to take your specific color palette from the Vision control and get it in array format and feed it into the array simulating the color bar. I included a VI that should allow you to do this. I have a horizontal version. You might want to make a vertical version and repost.
I would expect that future versions of the vision control should have a color ramp associated with them just as does the intensity graph.
Sincerely,
Don