AR Adjustments with it's own Exchange Rate Date

We are trying to work out a semi-automatic settlement program for IC Invoices in certain Foreign Currencies.

The first step is to close the outstanding AP Invoices using a specific Payment Templates. The Internal Bank Account used is a 'dummy' bank, linked to a 'Netting Account'.

On the AR side we developed a custom process which used the Auto Adjustment API, which picks up the invoices closed on the AP side and generates and Adjustment to close the balance

The GL Account used is that same 'netting account'.

Only problem is that the AP Payment DOES generate FX Gain/Loss and the AR Adjustment simply creates the activity using the Exchange Rate of the AR Invoice. So, no FX GainLoss is generated.