New Post: header background

I'm trying this code:

$objDrawing = new PHPExcel_Worksheet_HeaderFooterDrawing();
$objDrawing->setName('PHPExcel logo');
$objDrawing->setDescription('PHPExcel logo');
$objDrawing->setPath('./images/phpexcel_logo.gif');
$objDrawing->setHeight(36);
$objDrawing->setCoordinates('D24');
$objDrawing->setOffsetX(10);


$objPHPExcel->getActiveSheet()->getHeaderFooter()->addImage($objDrawing, PHPExcel_Worksheet_HeaderFooter::IMAGE_HEADER_LEFT);

$objPHPExcel->getActiveSheet()->getHeaderFooter()->setOddFooter('&L&G');
$objPHPExcel->getActiveSheet()->getHeaderFooter()->setEvenFooter('&L&G');

I tried every imaginable tweak and failed.

I'm using excel 2010

regards