Take a look at the following regarding using the Skin element painter to draw controls:
http://www.devexpress.com/Support/Center/p/CQ40491.aspx
Robert, you may also want to look into using the XtraScrollable control in conjunction wit the RichTextEdit for skinned scroll bars. I think you just need to dock the RichTextEdit to the XtraScrollable control, and set the scrolling properties on the RichTextEditor to false.