How to change the weight before sending to fedex magento?

Question

In magento checkout page, after giving billing information and shipping information, i understand that these details are sending to fedex then the shipping rates are populating in chekout page, before sending theses details to fedex, i want to change the weight of the product, i Want to add additional weights for each products,

suppose user adding a product with weight of 2 pounds, i want to send these weight to 2*5 = 10pounds, how can i do that in magento? please help.

Answer 1

Finally i find out that it is happening in the sales/quote/item.php file, there is a function called setProduct, here we need to add addititonal info while setting data.

public function setProduct($product)
    {

        $batchQty = Mage::getModel('catalog/product')->load($product->getId())->getBatchQty();
        $roleId     = Mage::getSingleton('customer/session')->getCustomerGroupId();
        $userrole   = Mage::getSingleton('customer/group')->load($roleId)->getData('customer_group_code');
        $userrole   = strtolower($userrole);
        if ($this->getQuote()) {
            $product->setStoreId($this->getQuote()->getStoreId());
            $product->setCustomerGroupId($this->getQuote()->getCustomerGroupId());
        }
        if($userrole=="retailer" && $batchQty>0 ){
            $this->setData('product', $product)
            ->setProductId($product->getId())
            ->setProductType($product->getTypeId())
            ->setSku($this->getProduct()->getSku())
            ->setName($product->getName())
            ->setWeight($this->getProduct()->getWeight()*$batchQty)
            ->setTaxClassId($product->getTaxClassId())
            ->setBaseCost($product->getCost())
            ->setIsRecurring($product->getIsRecurring());
        } else {
            $this->setData('product', $product)
            ->setProductId($product->getId())
            ->setProductType($product->getTypeId())
            ->setSku($this->getProduct()->getSku())
            ->setName($product->getName())
            ->setWeight($this->getProduct()->getWeight())
            ->setTaxClassId($product->getTaxClassId())
            ->setBaseCost($product->getCost())
            ->setIsRecurring($product->getIsRecurring());
        }

        if ($product->getStockItem()) {
            $this->setIsQtyDecimal($product->getStockItem()->getIsQtyDecimal());
        }

        Mage::dispatchEvent('sales_quote_item_set_product', array(
            'product' => $product,
            'quote_item' => $this
        ));
        return $this;
    }