RE: How to handle wrong exchange rate Posting?
Did you create many entries already with the wrong exchange rate, or just a few ?
And the exchange rate has now been corrected?
Hmmm ... usually you can "change" the suggested exchange rate in the document or the journal line directly.
If the now corrected ex.rate gets suggested for your manual reverse transaction (through a journal or a document) you shoudl be able to change that to the old, wrong currency factor and then post it.
So the old transaction (with wrong rate) should equal the new transaction (also with the wrong rate).
If these are customer or vendor transactions make sure to apply these two entries.
And then post the transaction again, this time with the correct exchange rate.