Customize the Protected Text

Hi !
I have a problem whith this fonction in version 3.5.1

—————————

<?php
function my_password_form() {
    global $post;
    $label = 'pwbox-'.( empty( $post->ID ) ? rand() : $post->ID );
    $o = '<form class="protected-post-form" action="' . get_option( 'siteurl' ) . '/wp-pass.php" method="post">
    ' . __( "To view this protected post, enter the password below:" ) . '
    <label for="' . $label . '">' . __( "Password:" ) . ' </label><input name="post_password" id="' . $label . '" type="password" size="20" /><input type="submit" name="Submit" value="' . esc_attr__( "Submit" ) . '" />
    </form>
    ';
    return $o;
}
add_filter( 'the_password_form', 'my_password_form' );
?>

—————————
The text is changed, but when you enter the password and nothing !
You have an idea ?
thanks for your help !

[please allow more time to get a reply]