Does anyone know why I can't rewrite the _amount_line method on sale.order.line???

Maybe because it's a private function?

I'm not sure.

This doesn't work alone:

    def _amount_line(self, cr, uid, ids, field_name, arg, context=None):
    tax_obj = self.pool.get('account.tax')
    cur_obj = self.pool.get('res.currency')
    res = {}
    if context is None:
        context = {}
    for line in self.browse(cr, uid, ids, context=context):
        price = line.price_unit * (1 - (line.discount or 0.0) / 100.0)
        taxes = tax_obj.compute_all(cr, uid, line.tax_id, price, line.product_uom_qty, line.product_id, line.order_id.partner_id)
        cur = line.order_id.pricelist_id.currency_id
        #This gets the delivery_price
        total=0
        for delivery_line in line.delivery_lines:
            total+=delivery_line.delivery_price

        res[line.id] = cur_obj.round(cr, uid, cur, taxes['total'])+total
    return res

The only solution that I've found is rewrite the function and create the field again:

_columns = {
    'price_subtotal': fields.function(_amount_line, string='Subtotal', digits_compute= dp.get_precision('Account')),
}

Am I missing something? Or It's something that happens all the time?

Thanks,

Grover Menacho