Hi,
You would need to create sub menu items for your categories. So under the "e-shop" menu item, you would create a "gleitschirm" menu item of the type "category listing" for the corresponding category, and under that menu item, you would create another menu item for the variometer category.
Another solution would be to use a SEF extension like 4SEF where you can modify the SEF URLs of any page to whatever you want as it keeps the correspondance between the SEFed URL and the non SEFed URL in the database, instead of using the menu items to dynamically calculate the URLs with the default Joomla URL routing system.
