you have to give type="action" inside the button tag. And name should be given as your form view id which you wish to show

thanks abhishek.. bt my question is .. in openerp sales module as soon as i click confirm order button new manufacturing order is created(by workflow).. in the same way when i click confirm order button i want bom to be created automatically.. i want to get all info in sales order and update tat in bom..