Query on Multi currency in NAV 4.0 SP3

hardikit

Dear all,

One of our client uses multicurrency functionality. they have scenario like this:

They sell at 1000$ where 1$= 40 Rs. They get money from bank as bank discount where the rate is 1$ = 39.5 Rs.

This is Realized loss. After making the receipt, I run the batch job it changes the LCY amount in Bank ledger. But I could not get the track that against which Invoice or Receipt the entry has been made by system.

what about customer ledger? should it get updated as unrealized gain or loss? how? can someone tell the whole process?

So can anybody help me? wheather i m following a right path?