Add a "normal" page below woocommerce shop URL?

Hi there,

one of my customers wants to build a specific URL structure that combines everything related under a common slug.
For normal pages I can achieve that by creating a page hierarchy, using parent / child relationships between pages.
But they also want pages like shipping-costs or terms, which are of course related to the shop, to be located below the shop URL.
So, if the shop URL is http://www.daunenspiel.at/shop
the shipping costs should be located at http://www.daunenspiel.at/shop/shipping-cost

How would I achieve that?
The shop page is not available to be selected as parent for a page.

Thanks,
Christian
tethis IT, Austria