Yes, unfortunately this is not possible. The most important reason: I do not know how to code it
. But there is another one why I prefer my own palette of selected colors.
Other Flash tools have an RGB wheel like that, but then the colors are picked automatically. For example: When you choose a color for a hair style the light an dark areas are just made lighter /darker automatically by x %. I don't like this because in my eyes every color needs a different treatment. When you have a deep red small differences are enough to create good looking highlights and shadows. But with a light yellow you need bigger changes to make it look good. You can add black to red to make it look darker. But when you want a darker yellow it looks dirty if you just add black. I add orange as well.
So this is the reason why I prefer handpicked colors. I choose the light and dark counterparts for each color myself to make the hairstyles and other items with lights and shadows look as good as possible.
I hope I was able to explain it