How to model losses and write offs in invoices?

Hi there,

what is the best way to "close" a partially paid invoice? I have this situation with foreign exchange effects causing problems with "overdue" invoices even though the transactions themselves are completed.

Kind regards,
Kiriakos

The core issue here being that, when doing taces, I would need to still declare the full amount as income and then subtract the FX effects. If I just change the invoice value all that info gets lost and I lose coupling documents outside akaunting, etc.