When I create and book a invoice for a advance payment on a sales order, the payment status of a this orders remains 'To invoice'.  How can this be changed to a different status, for example 'Partially invoiced'.

We are having the following conditions which I am yet unable to set-up in Odoo.

• 10% advance payment after order;
• • After receiving the 10% advance payment, PO will be send to our suppliers. 
• 90% payment before delivery;
• • After receiving the 90% rest payment, the product(s) will be send to customer.

It would be nice if we can monitor these conditions in the payment status for example.