Yes, right now the invoice form pulls by default from the Maintain/Information screen.  So for the DBA, just pull up the invoice and do a save as and give it a new name.  Delete the data field for the company name from that invoice form and insert a Text field and input the DBA company information.  You will then need to toggle the invoice form accordingly when in the Print or email screen, just select the Form button to switch it.  The system will default to the last used form each time.