producing bank statement in oracle 6i reports

Please help on the following :

I'm using Report Builder 6.0.8.25.0 and I need to produce a report giving the details of bank transaction per day, per customer.
The problem arise when a customer had done many transactions during the day and the report goes on many pages.

On the top I display the previous balance of the customer and at the bottom I need to display the balance at the given page means that at page one it will be the previous balance + the sum of transactions on that page . The problem is for following pages because par example for page 2 I need the amount displayed on bottom of page 1 so that I can add it to the sum of page 2 and display it on bottom of page 2 etc...

How can I keep that amount that changes after every new page.