Amountcur to AmountmstSecond

Hi friends,

I have to calculate amount mstSecond field i.e there in ledgertranstable.This Field is a calcualted field which is a conevrsion of amountmst feild to secondary currency.

I also want to calucatae it somewhere in secondary currency.

I am using CurrencyExchHelper class and using its method //CalculateamountmstToSecondary.

When i am calling this method i pass currency still i get the error .

“CURRENCY CODE IS NOT SPECIFIED>” Followed i sthe piece of of code I used.

exch = CurrencyExchHelper::construct();

ltr1.AmountMSTSecond = Exch.calculateAmountCurToSecondary(ltr1.AmountCur);

Please guide.