The Vostro Monitor lists the aggregated balances of each counterparty that is marked as a vostro account. These balances are organized by currency. To access the Vostro page, click on Reporting > Vostro Monitor in the navigation pane.
If you would like to see the detailed transactions that make up a specific balance for a vostro account, you can click into the corresponding vostro name. This will open up the Counterparty Summary page (as shown in the video below) which you can use to view the cash balances.