I meant that i can access to the data through the field invoice_ids, but i can not use it in a new form to change the values, as example: if my invoice originally i set the currency to US and y want to change it in the payment in pounds, i need to get the selected data in the invoice, and change it in the new form, cause if i recreate the field in the "account_payment" table then i have the same information in two tables.