how do I..

* edit the color of the msg box (not where you type, but around it, where B, I, U, and smileys are)
* set a bg picture in the msg box

Try experimenting with the main css of that style ;). .vBulletin_editor Is a good place to start

strangest thing but it doesn't show anything,
all other styles do in admincp CSS but that one doesn't.

So really hard to edit.

Do you mean there isn't a box for it or it just doesn't have anything entered?

nothing is in the boxes.
for other skins I see colors filled in and imagebgs and so on in the css admin
but for that skin nothing is filled in.

greetz

That's because it's using default CSS.. To use custom css just add some code to the boxes.