Hi Carsten,
Thanks for contacting Syncfusion support.
We have made a sample for your requirement by using our DatePicker control for achieving date Format and your German locale support in Listview template. Here we have used Listview template and overridden ejDatePicker CSS in sample level. Please find the sample in below link for your reference,
Also check the shared sample, information and if the shared details still doesn’t meet your requirement, please let us know, so that we will provide an alternate solution.
Regards,
Arun P.