Hey,
I did some testing on that control and found that the color is being set by the skin. For most AC controls you can set the SkinData.CustomColor property and that allows you to override the color but that isn't working for this control (this may be a bug or intended design idk).
What you can do to get it working now is change the SkinData.SkinSection to something other than GAUGE – I found that pressing DELETE so there is no skin section at all worked fine (it will show as UNKNOWN), but you may want to make it a PANEL or something else if you want to effect the way the border and other details of the control are drawn.
I hope that helps, best of luck.
Regards,
Hamilton