Hello, 

I have a new field in sale_order named: myfield

Now when I create a invoice from the sale_order , the myfield value is empty in invoice.

How can I move the value from my new field to invoice, when it creates a new invoice from the sale_order.

I tried something like this:

I see that the _prepare_invoice function is used to put values from sale_order to invoice.

Now when I make something like this it's not working.

I have the same field in invoice like "myfield" in sale_order:

def _prepare_invoice(self, cr, uid, order, lines, context=None):
    """Prepare the dict of values to create the new invoice for a
       sales order. This method may be overridden to implement custom
       invoice generation (making sure to call super() to establish
       a clean extension chain).

       :param browse_record order: sale.order record to invoice
       :param list(int) line: list of invoice line IDs that must be
                              attached to the invoice
       :return: dict of value to create() the invoice
    """
    if context is None:
        context = {}
    journal_ids = self.pool.get('account.journal').search(cr, uid,
        [('type', '=', 'sale'), ('company_id', '=', order.company_id.id)],
        limit=1)
    if not journal_ids:
        raise osv.except_osv(_('Error!'),   
            _('Please define sales journal for this company: "%s" (id:%d).') % (order.company_id.name, order.company_id.id))
    invoice_vals = {
        'myfield': order.myfield,

    }