Magento Block Paypal Rewrite

Question

I try to rewrite core file from Magento. But after rewrite the block it was not accessible and I don't know why?

The File I try to rewrite is : Mage_Paypal_Block_Standard_Redirect

The xml config (locate: app/local/Ga/etc/config.xml) :

<global>
    <models>
        <ga>
            <class>Ga_Model</class>
        </ga>
    </models>
    <blocks>
        <ga>
            <class>Ga_Block</class>
        </ga>
        <paypal>
            <rewrite>
                <standard_redirect>
                    Ga_Block_Paypal_Standard_Redirect
                </standard_redirect>
            </rewrite>
        </paypal>
    </blocks>
    <helpers>
        <ga>
            <class>Ga_Helper</class>
        </ga>
    </helpers>
</global>

The custom block (locate: app/local/Ga/Block/Paypal/Standard/Redirect.php):

class Ga_Block_Paypal_Standard_Redirect extends Mage_Paypal_Block_Standard_Redirect {
    protected function _toHtml()
    {
        return 'test';
    }
}

Paypal controller call the block like that :

public function redirectAction()
{
    $session = Mage::getSingleton('checkout/session');
    $session->setPaypalStandardQuoteId($session->getQuoteId());
    $this->getResponse()->setBody($this->getLayout()->createBlock('paypal/standard_redirect')->toHtml());
    $session->unsQuoteId();
    $session->unsRedirectUrl();
}

"createBlock" method return nothing after the rewrite.

I have no idea what I'm doing wrong.

Thanks

EDIT : I have found the solution. The problem come from the fact it's necessary to write the custom block class in one line like that :

    <blocks>
        <ga>
            <class>Ga_Block</class>
        </ga>
        <paypal>
            <rewrite>
                <standard_redirect>Ga_Block_Paypal_Standard_Redirect</standard_redirect>
            </rewrite>
        </paypal>
    </blocks>

Answer 1

Follow this structure

<global>
<blocks>
    <paypal>
        <rewrite>
             <standard_redirect>MyNamespace_MyModule_Block_Standard_Redirect</standard_redirect>
        </rewrite>
    </paypal>
</blocks>
<global>