Additional processing of data submitted my commerce_payment_method_redirect_form

Thanks or your reply, unfortunatly I'm a bit pushed for time so had to do a work around solution.

Other's out there may find it useful, however I've looked at serveral hosted payment solution modules and they all seem to post the data directly to the payment provider. Which is OK if the payment provider doesn't mind receiving drupal fields such as form_build_id, form_id and form_token.

I had to remove those fields, then create a form where the form keys are ordered alphabetically. (a requirement of Suncorp).

Then hash the data on the server side and add the hash to the submit button value. Rename the submit button to vpc_SecureHash.

Then a nasty css hack to remove the submit button value as this is the hashed data (must be the LAST value submitted to Suncorp, yay)

This is by no means a work of art, in fact a bit of a hack/workaround, I'd love to hear a better solution if someone can provide it.

Just want to modify the data server side however then submit to the payment gateway however drupal_goto seems to stop the form validation and submit flow.

    function commerce_suncorp_virtual_pos_3_party_redirect_form($form, &$form_state, $order, $payment_method) {
 
		$settings = $payment_method['settings'];

		//$return = url('checkout/' . $order->order_id . '/payment/return/' . $order->data['payment_redirect_key'], array('query' => array('payment_amount' => '', 'bank_reference' => '', 'payment_number' => ''), 'absolute' => TRUE));
		$return = url('checkout/' . $order->order_id . '/payment/return/' . $order->data['payment_redirect_key'], array('absolute' => TRUE));

		$vpcURL =  trim($settings['commerce_suncorp_payment_url']) . '?';

		// Set up the initial form.
		
		$form['#action'] = $vpcURL;
		$form['#method'] = 'get';

		$data['vpc_Merchant'] = trim($settings['commerce_suncorp_merchant_id']);
		$data['vpc_AccessCode'] = trim($settings['commerce_suncorp_merchant_access_code']);
		$data['vpc_Version'] = '1';
		$data['vpc_Command'] = 'pay';
		$data['vpc_Locale'] = 'en';
		$data['vpc_MerchTxnRef'] = trim($setting['vpc_MerchTxnRef']);
		$data['vpc_Amount'] = $order->commerce_order_total['und'][0]['amount'];
		$data['vpc_MerchTxnRef'] = $order->order_number . '-' . time(); 
		$data['vpc_ReturnURL'] = trim($settings['url']);
		
		
		// Create the request to the Virtual Payment Client which is a URL encoded data
		// request. Since we are looping through all the data we may as well sort it in
		// case we want to create a secure hash and add it to the VPC data if the
		// merchant secret has been provided.
		$md5HashData = trim($settings['commerce_suncorp_secure_hash']);
		ksort($data);
		

		foreach($data as $key => $value) {

			// create the form elements in alphabetical order
			if (strlen($value) > 0) {
				
				$form[$key] = array(
					'#type' => 'hidden',
					'#value' => $value
				);
				
				//add values to the data to be hasheddrupal drupal 
				$md5HashData .= $value;
			}
			
			
		}
		
		// Create the secure hash and apply it to the submit button as this form can't be manipulated after submit
		$form['submit'] = array(
			'#name' => 'vpc_SecureHash',
			'#type' => 'submit',
			'#value' => strtoupper(md5($md5HashData)),
		);
		
		$form['#token'] = false;
		$form['#pre_render'][] = 'suncorp_virtual_pos_3_party_unset_default_form_elements';
		dpm($form);
		return $form;
    }


	function suncorp_virtual_pos_3_party_unset_default_form_elements($form){
		unset($form['form_token']);
		unset($form['form_build_id']);
		unset($form['form_id']);
		return $form;
    }