Setting field 0 in the header using LaTeX fancyhdr

Question

I am trying to define my own layout for my report, for which I am using fancyhdr. On pages that contain the beginning of the chapter, I want my title to contain a colorbox that spans the entire page (0 cm margins), although I kept the default marker in the text area. I can get a box that will cover the margin notes area, but not from the other side. Here are some of my code:

\fancypagestyle{plain}{ % pages containing chapter start
    \fancyhead{}
    \fancyhead[RO]{\colorbox{NavyBlue}{\textcolor{White}{\raisebox{0cm}[1cm][0.5cm]{\makebox[3cm][c]{\textbf{\CNoV\thechapter}}}}}
}

Any ideas on how to do this?

UPDATE

alt text http://docs.google.com/File?id=dg4jt6qx_10nnpxfqdj_b

As you can see, I want my title to cover the entire page (on pages containing the beginning of the chapter). The text should have normal margins.

Answer 1

texample.net. , , .

alt text http://media.texample.net/tikz/examples/PNG/fancy-chapter-headings.png

Answer 2

, , , , :

\fancypagestyle{plain}{ % pages containing chapter start
        \fancyhead{}
        \fancyhead[RO]{\hspace*{-5cm}
        \colorbox{NavyBlue}{\textcolor{White}{\raisebox{0cm}[1cm][0.5cm]{\makebox[25cm][c]{%
            \textbf{\CNoV\thechapter}}}}}}
}