I'm fairly sure that the location of the helpers doesn't matter, because any helper with your prefix is loaded from the path and the module is not taken into consideration.
PHP Code:
$viewRenderer = Zend_Controller_Action_HelperBroker::getStaticHelper('viewRenderer');
$viewRenderer->initView();
$viewRenderer->setViewSuffix('php');
//include our custom helpers
$viewRenderer->view->addHelperPath(APPLICATION_DIRECTORY . '/views/helpers', 'My_View_Helper');