If return debit charges have been incurred, you can charge these charges to your customers. You can find instructions on how to bill bank processing fees here.
billwerk is informed of the exact amount of the fees listed due to return debit notes or credit card chargebacks by the payment service provider.
Since only the exact fees charged by the bank are passed on to the customer, this is real damage compensation (see Schleswig-Holsteinisches Oberlandesgericht, judgement from 26.03.2013, Az.: 2 U 7/12).
Real damage compensations are treated tax-free and therefore return debit charges are listed separately from other claims on billwerk's invoices at 0.00% VAT.
For processing fees, billwerk thus also has a separate revenue account for each country, which can be configured in accouting export. Further information can be found here.