how to add sku and order id sold product report in magento?

[pankaju]

i want sold product sku's and order id in below
code\core\Mage\Adminhtml\Block\Report\Product\Sold\Grid.php

i tried to below code but showing blank

$this->addColumn('sku', array(
'header' =>Mage::helper('reports')->('SKU'),
'index' =>'sku',
));
$this->addColumn('order_increment_id', array(
'header' => Mage::helper('reports')->('Order'),
'index' => 'order_increment_id',
));