Redirecting the buyer to the payment page

The URL of the payment gateway is:
Example of parameters sent to the payment platform:
<form method="POST" action="https://secure.payzen.eu/vads-payment/">
<input type="hidden" name="vads_action_mode" value="INTERACTIVE" /> 
<input type="hidden" name="vads_amount" value="2990" /> 
<input type="hidden" name="vads_capture_delay" value="0" /> 
<input type="hidden" name="vads_ctx_mode" value="TEST" /> 
<input type="hidden" name="vads_currency" value="978" />
<input type="hidden" name="vads_cust_country" value="FR" />
<input type="hidden" name="vads_cust_email" value="nom.prenom@exemple.com" />
<input type="hidden" name="vads_page_action" value="PAYMENT" /> 
<input type="hidden" name="vads_payment_config" value="SINGLE" /> 
<input type="hidden" name="vads_site_id" value="12345678" /> 
<input type="hidden" name="vads_trans_date" value="20140526101407" /> 
<input type="hidden" name="vads_trans_id" value="362812" /> 
<input type="hidden" name="vads_validation_mode" value="0" /> 
<input type="hidden" name="vads_version" value="V2" />
<input type="hidden" name="signature" value="86b2a17b9a5fcefb6c0120c57b25ec86ad1704ee"/>
<input type="submit" name="payer" value="Payer"/>
</form>