When running the purchase ledger/accounts payable report you can include on account payments with prepayment numbers. These will be detailed below the invoice lines when the Purchase ledger/accounts payable report is run in Detailed or Overview mode.

When the report is run as Aged, the on account values will not be displayed by default. There is a new setting in version 7.0 which now allows you to specify that the Prepayment Total be included as a separate column in the Aged report. This setting is found in Sales Ledger>>Setting>>Aged Limits and applies to both the Sales Ledger/Accounts Receivable and Purchase Ledger/Accounts Payable modules.