Helpers in Zend_View: Class Prefix

I have to say, the Zend Framework documentation is a bit imprecise sometimes. Regarding custom Helpers in Zend_View it states:

The class name must, at the very minimum, end with the helper name itself, using CamelCaps. E.g., if you were writing a helper called "specialPurpose", the class name would minimally need to be "SpecialPurpose". You may, and should, give the class name a prefix, and it is recommended that you use 'View_Helper' as part of that prefix: "My_View_Helper_SpecialPurpose". (You will need to pass in the prefix, with or without the trailing underscore, to addHelperPath() or setHelperPath()).

What does that mean regarding how your Helper has to be called? The default prefix for a Helper function that should be called foobar() is actually:

class Zend_View_Helper_Foobar()
{
    function foobar() { }
}

It took me some time to realize that. Why doesn't Zend just give an example like that? To change the prefix in a context of the Zend_Controller_Action you have to do something like this:

class SomeController extends Zend_Controller_Action
{
    function init() {
        $this->initView();
        $this->view->addHelperPath("pathtohelpers", "ClassPrefix");
    }
}