Witholding tax in Receivables

Good morning!

Our company wants to send invoices with "witholding tax" to customers.

  We have an invoice with a base amount of 4000€, it's tax is 720€ (18%) both amounts have to be paid by the customer to us and the customer have to pay to the administration an amount of 760 (19% of the base amount). Of course we have to reflect this in ar and gl.

We are trying with adjustments, but all of our invoices came by interface from another system, and we are not able to make an adjustment with the interface.

As we read in a note (3187736) in receivables we cannot do this, but we are sure that we are not the first in doing this!