Adding some Values to Running Total in Crystal Report 8.5

Hello
I m creating Account Ledger Report in Crystal Report 8.5.
I have put DATE , DESCRIPTION , DEBIT & CREDIT fields from Tbl_Ledger
and for balance i have created a Formula (RemBal) and write the code Tbl_Ledger.Debit - Tbl_Ledger.Credit

This (RemBal) has put it in Running Total.
I also have a formulafiled LASTBALANCE which value is = 500

I want to add that LastBalance value in Running Total but it effects on all rows.


How can i do this ?

Please help me

thanks in advance
Farooq

Moved to reporting section