Notice: Argument 2 passed to Mage_Core_Model_Config::_makeEventsLowerCase()
must be an instance of Mage_Core_Model_Config_Base,
instance of Mage_Api_Model_Wsdl_Config_Base given

class Mage_Api_Model_Wsdl_Config_Base extends Mage_Core_Model_Config_Base

$mergeWsdl = new Mage_Api_Model_Wsdl_Config_Base();