How can I create and update a document in two doctypes?

Let me explain what I want to do:
I have a DocTyoe called “Order”, it contains a list of orders in it.
I want to create another DocType called “Invoice” which contains the order information, customized for Financial Manager.
When I create a new “Order”, I want it to create two documents, one in Order, and one in Invoice. With the same data. Also when I change a document in Order, it should change in the Invoice too!

Thanks a lot!

Implement this in your hooks file of the oder doctype on after_submit