Give Store URL for PHTML Pages in Magento

add in your confix.xml in

<frontend>
            <routers>
                <customer>
                    <args>
                        <modules>
                            <company_modulename before="Mage_Customer">Company_Modulename</company_modulename>
                        </modules>
                    </args>
                </customer>
            </routers>
        </frontend>

these is you controller

require_once 'Mage/Customer/controllers/AccountController.php';
class Company_Modulename_AccountController extends Mage_Customer_AccountController
{
    public function logoutAction()
{
    $this->_getSession()->logout()
        ->renewSession();
      //add your code here
    $this->_redirect('*/*/logoutSuccess');
}
}

I think you need to create a new controller action and then call it when you click on "Create custom product" button in your phtml

public function createSimpleProductAndRedirectAction()
{
    if($product = $this->_createProduct(Mage_Catalog_Model_Product_Type::TYPE_SIMPLE)){
        $this->_redirect("catalog/product/view/id/".$product->getId());
    }
}

Now use this action in your button href

<button type="button" > 
    <span> 
        <a href="<?php echo Mage::getUrl("example/amasty/createSimpleProductAndRedirect"); ?>">created simple product</a>
    </span> 
</button>