Possible to Add Old/Paid Invoices (History)?

Possible to Add Old/Paid Invoices (History)?

Hi,

We are basically moving our accounting/invoicing from an online service to Zoho Invoicing, and I was wondering if it is possible to enter already entered/paid invoices to the system so that we can have complete (back)history on file. What I mean is to enter for example an invoice from March 2008, using the old invoice numbering system, and then mark it as paid, etc so that old invoices are all kept on the system in once place. Is something like this possible?

Thanks,
Anthony