Hi Mohit,
Actually, there is no difficult to do FCV for Bank account.
I hope you've maintained account for transaction KDB in tcode OBA1.
The bank account should be ticked on Line item display, and currency is different with currency in Valuation Area in FCV.
Example: When you choose Valuation Area for currency USD, the currency of Bank account should be different with USD.
When run FCV, you choose tab GL balances, tick on Valuate GL account balance, fill your bank account and run as normal.
If you have any error, please tell me.
Julie