[wp-e-commerce] variables to integrate a payment gateway

I want to integrate a payment gateway that′s very popular in my country with wp-e-commerce. I need the button to charge the information in wp-e-commerce chart when checking out.
Where in the template files can I find the variables to fill this form?
(the expample form they gave me in DineroMail to integrate)

<form action="https://checkout.dineromail.com/CheckOut" method="post" >
<!-- Sale settings -->
<input type="hidden" name="tool" value="cart" />
<input type="hidden" name="merchant" value="0001" />
<input type="hidden" name="seller_name" value="E-Commerce" />
<input type="hidden" name="languge" value="es" />
<input type="hidden" name="transaction_id" value="11122233" />
<input type="hidden" name="currency" value="ars" />
<input type="hidden" name="ok_url" value="https://www.ok.com" />
<input type="hidden" name="error_url" value="https://www.error.com" />
<input type="hidden" name="pending_url" value="www.pending.com" />
<input type="hidden" name="additional_fixed_charge" value="5" />
<input type="hidden" name="additional_fixed_charge_currency" value="ars" />
<input type="hidden" name="buyer_message" value="1" />
<input type="hidden" name="header_image" value="https://www.ecommerce/Logo.gif" />
<input type="hidden" name="header_width" value="1" />
<input type="hidden" name="change_quantity" value="1" />
<input type="hidden" name="display_shipping" value="1" />
<input type="hidden" name="display_additional_charge" value="1" />
<input type="hidden" name="expanded_step_ PM" value="0" />
<input type="hidden" name="expanded_step_ AD" value="0" />
<input type="hidden" name="expanded_step_ SC" value="0" />
<input type="hidden" name="expanded_sale_
<input type="hidden" name="item_weight_1" value="0400" />
<input type="hidden" name="shipping_currency_1" value="ars" />
<!-- Item 2 -->
<input type="hidden" name="item_name_2" value="MP3" />
<input type="hidden" name="item_code_2" value="021" />
<input type="hidden" name="item_quantity_2" value="1" />
<input type="hidden" name="item_ammount_2" value="8000" />
<input type="hidden" name="item_currency_2" value="ars" />
<input type="hidden" name="shipping_type_2" value="2" />
<input type="hidden" name="shipping_cost_1_2" value="1000" />
<input type="hidden" name="shipping_cost_2_2" value="500" />
<input type="hidden" name="shipping_currency_2" value="ars" />
<!-- Buyer info -->
<input type="hidden" name="buyer_name" value="Juan Carlos" />
<input type="hidden" name="buyer_lastname" value="Lopez" />
<input type="hidden" name="buyer_sex" value="m" />
<input type="hidden" name="buyer_nacionality" value="arg" />
<input type="hidden" name="buyer_document_type" value="dni" />
<input type="hidden" name="buyer_document_number" value="12345678" />
<input type="hidden" name="buyer_email" value="jclopez@buyer_email.com" />
<input type="hidden" name="buyer_phone" value="55555555" />
<input type="hidden" name="buyer_phone_extension" value="123" />
<input type="hidden" name="buyer_zip_code" value="1234" />
<input type="hidden" name="buyer_street" value="buyer_street" />
<input type="hidden" name="buyer_number" value="123" />
<input type="hidden" name="buyer_complement" value="buyer_complement" />
<input type="hidden" name="buyer_city" value="buyer_city" />
<input type="hidden" name="buyer_state" value="buyer_state" />
<input type="hidden" name="buyer_country" value="arg" />
<!-- Color Design -->
<input type="hidden" name="step_color" value="E7E7E7" />
<input type="hidden" name="hover_step_color" value="DFEFFF" />
<input type="hidden" name="links_color" value="0000D4" />
<input type="hidden" name="font_color" value="6699CC" />
<input type="hidden" name="border_color" value="F99800" />
<input type="hidden" name="button_color" value="6699CC" />
<!-- Additional data -->
<!-- Item 1 -->
<input type="hidden" name="additional_var_description_1" value="XXXXXXX" />
<input type="hidden" name="additional_var_value_1" value="XXXXXXX" />
<input type="hidden" name="additional_var_visible_1" value="1" />
<input type="hidden" name="additional_var_required_1" value="0" />
<!-- Item 2 -->
<input type="hidden" name="additional_var_description_2" value="XXXXXXX" />
<input type="hidden" name="additional_var_value_2" value="" />
<input type="hidden" name="additional_var_visible_2" value="1" />
<input type="hidden" name="additional_var_required_2" value="0" />
<input id="Submit" type="submit" value="button" />
</form>

Thanks!