Sending data via post and redirecting user So I made a module that needs to gather some data and redirect user and that data to a payment site.

function payment_upload_form($form, &amp;$form_state){


$form = array();    
$form['#action'] = 'www.somepaymantsite.com';
$form['#method'] = 'POST';
$form['CustomerFirstName'] = array(
    '#title' =&gt; t('First name'),
    '#type' =&gt; 'textfield',
    '#required' =&gt; TRUE,
    '#size' =&gt; 25,
);

$form['CustomerLastName'] = array(
    '#title' =&gt; t('Last name'),
    '#type' =&gt; 'textfield',
    '#required' =&gt; TRUE,
    '#size' =&gt; 25,
);
etc....

$form['customersubmit'] = array(
        '#value' =&gt; 'Pay now',
        '#type' =&gt; 'submit',
        '#submit' =&gt; array('wspay_submit'),
    );

return $form;

}

function payment_submit($form, &amp;$form_state){
$option = array(
        'ShopID'=&gt;'xzy',
        'ShoppingCartID' =&gt; $temp_cid,
        'TotalAmount'=&gt; $amount,
        'Signature' =&gt; $signature,
        'ReturnURL' =&gt;'http://some_sitecom',
        'CancelURL' =&gt; 'http://some_site.com',
        'ReturnErrorURL' =&gt; 'http://some_site.com/1',
        'CustomerFirstName' =&gt; $form_state['values']['CustomerFirstName'], 
        'CustomerLastName' =&gt; $form_state['values']['CustomerLastName'], 
        ....
        );

$options = array(
  'method' =&gt; 'POST',
  'data' =&gt; drupal_http_build_query($option),
  'timeout' =&gt; 15,
  'headers' =&gt; array('Content-Type' =&gt; 'application/x-www-form-urlencoded'),
);

$response = drupal_http_request('www.somepaymantsite.com', $options);
 $response-&gt;redirect_url = 'www.somepaymantsite.com';


The problem is that it does not redirect me on the first go, but when I use the same ShoppingCartID it redirects me and I get an error because the ID is the same(it need's to be different every time), but the data is in the URL .
So my question is why does it not redirect the user with the data to the site when he clicks Pay now.

---------------------- EDIT -------------

How can i create a middle page in drupal that has this data and sends it like that, meaning a confirmation page : 

        &lt;form name=“pay“ action=“https://to.the.shop.something“ method=“POST“&gt;
    &lt;input type=“hidden“ name=“ID“ value=“some_value“&gt;
    &lt;input type=“hidden“ name=“ID2“ value=“some_value“&gt;
 &lt;input type=“hidden“ name=“ID3“ value=“some_value“&gt;
    &lt;input type=“submit“ value=“Pay now“&gt;
    &lt;/form&gt;
Your submit function name is wrong , your submit function not called at all, In Drupal if you have form name x then the submit should be x_submit, so in your case the submit function should be

payment_upload_form_submit