Hi @archix007,
I guess you're talking about this method:
/**
* Retrieve order billing address
*
* @return Mage_Sales_Model_Order_Address
*/
public function getBillingAddress()
{
foreach ($this->getAddressesCollection() as $address) {
if ($address->getAddressType()=='billing' && !$address->isDeleted()) {
return $address;
}
}
return false;
}
Is located on app/code/core/Mage/Sales/Model/Order.php, line 952.
You should check that $address has your attributes.