Create a new atonav template:
Copy the view.php file from /concrete/blocks/autonav/view.php -> to /blocks/autonav/templates/newviewname.php (and rename it)

Inside that file there is this line:
$navItems = $controller->getNavItems();

Add the word 'true' to the parameters of the function:
$navItems = $controller->getNavItems(true);

This will override the normal operation of atonav and will ignore the 'Exclude From Nav' page properties. Especially useful for creating your site map page. Now place your atonal block and apply your new template.

Hope this helps someone out there.