I am going to guess that you are using the Receivable Module. When an amount paid on account is received you go to the Receipts module and post a pre-paid deposit. This shows in the Receipts screen when you click on the icon that looks like a safe. This is fifth from the left in the row of icons. When you click on this icon there will be some extra fields open at the bottom of the screen where you enter a customer deposit. Before posting check the journal entry CTRL+J. The debit will be to the bank and the credit should be to 2460 as it is a linked account. Being a linked account is the reason you cannot post to it directly.