How to add default text in product's short description woocommerce

I have installed woocommerce, so I have products.
In the page where you create products (in the backend, when you click ‘add new product’) there are: the standart editor of wp, the panel with woocommerce options and another editor called ‘short description’.
In the ‘Short description’ I need to insert a default text inside the editor, so you can see the defaut text and then adding your description.
Here you can see a screenshot modified with the result: http://i61.tinypic.com/34q4k9l.png

In other words, I need that default text shows up automatically in the “Short Description” field whenever I add a product.

I’ve found this for the content editor of standard post: http://www.wpbeginner.com/wp-tutorials/how-to-add-default-content-in-your-wordpress-post-editor/
I’ve tried with the code below, but doesn’t work.

add_filter('woocommerce_short_description', 'my_editor_content', 10, 2);
function my_editor_content( $content ) {
$content = 'The default text, imposed by me, needs to be here in every product.';
return $content;
}

Anyone can help me?
Thanks