Foreign credit invoice for ticket income from event presales

Every 14 days, I receive a credit invoice from a foreign (European) ticket provider. This credit invoice always states the ticket revenue, as well as the service charges and transaction costs that are deducted. I therefore book this as a sales invoice. My former accountant always recorded the ticket revenue at 6% (reverse-charged vAT for IC Services) via the sales invoice and then the service charges (negative amount) that were deducted at 21% (reverse-charged vAT) and the transaction costs at 0% (reverse-charged vAT). All this in different lines in one and the same sales invoice.

I notice in Dexter that the reverse-charged VAT for my customer (European ticket provider) cannot be selected, so apparently it is automatic (but then I am not sure that the ticket revenue is reverse-charged to the desired 6%). In addition, I cannot add an item to the sales invoice for the service costs, nor can I indicate the reverse-charged vAT percentage for this. How should I best handle this? Who can help me with this?