If an item with a live listing goes out of stock, the listing template is placed in a 'Pending relist' status and will be relisted when more stock arrives.
Currently it is not possible to create a new listing template for an item that has no stock, so if the item has never been listed, you cannot create a template for it.
It would be much better if you were able to create listing templates for out of stock items, but they too were created with a 'Pending relist' status, so that they are listed when stock arrives.
It's very difficult to get a large inventory with changing stock figures online, as you need to manually attempt to create listings daily in order to catch items that were out of stock when you last tried. Allowing a new template for an out of stock item would resolve this problem.