Clearing of foreign currency documents in different posting date
I have encountered an issue on the foreign exchange clearing.
Example given as below Accruals was made on 31 Aug 2008 (Cr Balance), when the invoice is received on 25 Sept 2008, this transaction will be reversed (Dr Balance). And we need to trigger the clearing/matching process. The document currency of the accruals was SGD, but the invoice comes in GBP. Hence, by right, when the invoice is received on 25 Sept 2008, the system should pick the foreign currency rate on this date - WHICH IS 25 Sept 2008.However, the current practice is it depends on which date we do the matching/clearing. Say, if we clear on 20 Sept 2008, the system will pick the 20 Sept 2008 date currency rate, which gives a realised gain/loss (SGD: 716.80 or USD 500.28).
How to pick up the right currency rate we needed?