CodeIgniter：2个按钮，一个表单，不同的操作

so I am adding another payment type in my system. I have one form which posts the values to a controller. In that controller based on the values of the submit it would redirect to the different functions for payment. However in one case it still goes to the main action that is mentioned in the form, Kindly find the code mentioned below:

CONTROLLER:-

        if ($this->input->get_post('order_type')=="order") {
            $payment_type = $this->input->get_post('submit_btn');

            if($payment_type == "Payvision"){   
                $this->basicauth($id);          
            }
            else if($payment_type == "Sagepay"){
                $this->make_payment($id);
            }
        } 

VIEW:-

    <?php echo form_submit('submit_btn', 'Sagepay', 'class="btn btn-success"'); ?>
    <?php echo form_submit('submit_btn', 'Payvision', 'class="btn btn-success"'); ?>

The make_payment($id) works, it doesn't work for basicauth($id) It redirects to the same page. When I select the Payvision button.

Also adding the code for the basicauth function below:

public function basicauth($order_id = NULL){

    $this->load->model('customer_m');

    $order = $this->order_m->get($order_id);
    $customer = $this->customer_m->get($order->customer_id);


    $this->data['order_no'] = $order->order_no;
    $this->data['amount'] = $order->total;
    $this->data['currency'] = 826;
    $this->data['customer'] = $customer->name . ' ' . $customer->lname;
    $this->data['country'] = 826;

    $this->data['subview'] = 'agent/order/basicauth/PaymentRequest';
    $this->load->view('agent/_layout_main', $this->data);

}

Any help will be greatly appreciated.

VIEW (EDIT):-

<?php echo form_open('agent/order/edit/'.$order->id,array('class'=>'form-horizontal', 'name'=>'createorder')); ?>