Gateway Integration with PagSeguro


I want to integrate payment gateway with Brazilian PagSeguro, which works similar to PayPal. Can anyone help me filling the fields? These are the parameters:

<input name="receiverEmail" type="hidden" value="SELLER-MAIL">
<input name="currency" type="hidden" value="BRL">
<input name="itemId1" type="hidden" value="0001">
<input name="itemDescription1" type="hidden" value="SERVICE_NAME">
<input name="itemAmount1" type="hidden" value="PRICE">
<input name="itemQuantity1" type="hidden" value="QUANTITY">

I have tried replacing them with some . esc_attr . I have found along the code, but instead get the string "Payment for SERVICE", and cannot found the price variable.

I know this seems quite a tech question, but any help you be appreciated.