pdf invoice in duplicate

Hi, I have created a form in PDF invoice with scriptcase for creating precisely the invoice to print, the problem is that my clients need a form in duplicate, ie, on a A4 print out the same bill in double format, a and copy them to a customer …
you can do it???
Where should I intervene???

Is it an idea to print 2 copies on the printer (to be set in the printer menu)? And to send to the customer by email or on paper?
Regards, Bert