Yes, I managed to figure out those steps in Skin Studio.
Looks like only the 'Show Desktop' icon in the rightmost corner of the taskbar took the new color, rest of taskbar is as before for 'The Captain'. You also see the new 'image color' in the Window Blinds UI (at the bottom where you would expect it).
On a another topic, why are the choices on the Settings/Color page greyed out? Transparency, Start, taskbar and action center checkboxes?
(Is there a user guide for theme/skin customization?)