Opening balances - Accounts Receivable and Payable

Opening balances - Accounts Receivable and Payable

Our accounting year starts on 1st August 2013 and I have a Trial Balance as at that date, including Accounts Receivableand Accounts Payable balances, broken down by each customer and supplier.

Q1 - do I show my opening balance date as 31st July 2013 or 1st August 2013?
Q2 - how do I bring in the opening AR and AP balances as the boxes on the Opening Balances template is blocked for these items? Do I enter B/F balances in each of the relevant contact accounts as at 31 July 2013 and the total will then automatically come through to the Opening Balances template?