Payables Invoice Number Entry

Is there a way to restrict  the entry of the invoice number to prevent the automatic date entry as the invoice number?

For example, if entering an invoice in payables and the invoice date is November 1, 2009 and the invoice number is 12345, the invoice date would be entered as 01-NOV-2009. However, if you skip by the invoice number field, the system prompts you if you would like to "use the invoice date as the invoice number"? Therefore, if you accept this prompt, the invoice number would also be 01-NOV-2009 instead of the correct number of 12345.

Is there a way to prevent this from happening? I would like to make sure my staff enters the correct invoice number and that they don't bypass the invoice number entry field and have the date entered automatically (purposely or accidentially). I would like to turn off the automatic invoice number entry process.