Thanks everybody.
I sat all night, but got it right. I just to had to find files that really put header och footer for the hole forum to integrate into my table.
After a while I found an easy way. All you have to do is to edit this files:
include/page_header.php
include/page_tail.php
This files send a request for some tamplates (NOTICE *.TPL):
templates/subSilver/overall_header.tpl
templates/subSilver/overall_footer.tpl
The to first files include a code (PHP) of this exemple:
$template->set_filenames(array('overall_header' => 'overall_header.tpl'));
....
...
...
$template->pparse('overall_header');
So all you have to do is include in this files your header! Yee, well but don't forget that some of the HTML STYLE tags then have to be removed from the above mentioned template files.
REMEMBER that the templates files doesn't approve php code if you want toput some in the middle. Then you have to split the template file and have a third file (YOUR file with php code).
The end of page_header.php looked something like this for it to work for me:
require('../header1.php'); // my file that include php
require('../meny.php'); // my file that include php
$template->pparse('overall_header'); // template file I split in two
require('../header2.php'); // my file that include php
require('../um_index.php'); // my file that include php
$template->pparse('overall_header2'); // 2:nd template file I
// created. No php in this
// one.
Well that's it. Hope that will help somebody. You only have to simply edit 4 files, but no one writes about it in the forums anybody suggested.