Hi Priya,
I will try to share as far as I know.
As below, we use the position management procedure 2500 with FC valuation. In our case, we also activated the exchange gain/loss clearing so we need to mark V252 and V253 as posting relevant.
Next you check which update types you have assigned in Assign Update Types for Derived Business Transactions for posting outflow (5th tab) - Foreign Currency Valuation for the position management procedure.
We made these update types posting relevant and assigned with posting specs to move unrealised FX to realised FX.
hope that this helps
taro