This is probably possible, but before I start digging around, why don't you edit in "html" mode?

That way you can setup spans/divs/etc to change the background and text colors without this hassle.

First of all: thanks for taking the time to respond.

Why not use html is easy...
I cannot expect all users that possible edit texts on my sites (like on a forum, feedback) have knowledge of html.
i like skins that are black or darkblue (space games) and i have a lot of work to edit the texts. i have used telerik editor in the past, because it could use skintags to show the proper colors. However, i'm not that good in skinning and such and i would like to be able to switch quickly with skins. (or enable users to select their own skin) now i am "limited" to using skins with dark letters. I just had some hope that "edit content" would use the skin background colors so i can see in a glimpse how it will look. I have similar problems with fontsizes and sometimes font types... look good in edit content, but on the site it looks smaller, bigger, thinner, different colors etc....

It's not a really big problem, only a minor annoyance.