If you require an invoice after purchasing hits, you can browse to your status page at
and download it from there.
Invoices are also available for past transactions.
The invoice will show the business name you have set in your Paypal account.
NOTE: It seems that the Paypal system takes a while to propagate the business name, so if you request the invoice too soon after completing the transaction only your email address will appear on the invoice. If you wait a day, it is likely that your business name will also show on the invoice above the email address.
Regards,
Sidd.