Colour the middle body with white

Good evening.

So now I'm loving the idea so far finished, but still need the last spark.
Please look briefly at times my test forum:

http://alfaromeotest.forumieren.com/portal.htm
There I provided by CSS is now the top part with a picture, also the footer of the forum.
What I need now is a code which the middle part is filled with white white colour.

Code:

body {
background-attachment:fixed;
background-color:#857171;
background-image:url(http://www.abload.de/img/weiyuo3.png);
background-repeat:no-repeat;
background-position:center;
}

I used also this code bute the code fills the forum from top to bottom with colour:

Just look here,please:
http://www.abload.de/image.php?img=12345jqsm.png

To show you what my Problem is i created a grafik for you. The blue lines show where i want to have white colour.
http://www.abload.de/image.php?img=sosollsseinpske.png

------------------

The two Codes i take for my testforum i will show you here:

For the background picture at the top:

Code:

#pun-intro {
  margin: 0;
  padding: 1.5em 1em 1em 1em;
  border-bottom: 0px solid #296fa5;
  background-color: transparent;
  background-image: url('http://www.abload.de/img/header2dmdm.png');
        background-position: center;
  text-align: left;
  background-repeat: no-repeat;
        height: 270px;
        margin-top: -5px;
        margin-left: -12px;
        width: 950px;
}

And this Code put a background picture into the footer.

#pun-foot {
background-image: url('http://www.abload.de/img/testfooter9t02.png');
background-repeat: no-repeat;
margin-left: -10px;
width: 950px;
background-position: bottom;
height: 400px;
margin-bottom: -5px;
}

-------------------------------
So what i need is a code, which couloured my middle part. Is it impossible to rewrite my Code above that it works ?

So guys i hope you will help me. The german support forum can't help until now so my hope is by you, guys.

Who wants to gain my respect for all the time ?

...

Sorry for my horrible english.

Cheers Lukas


EDIT
The result should be like this : http://demo.nicetheme.com/index.htm?theme_id=147647