The following information is from a customer who integrated his phpCoin with QuantumGateway
Use this code from the gateway modded part PHPcoin
<FORM METHOD=POST ACTION="https://secure.quantumgateway.com/cgi/web_order.php">
<input name="gwlogin" type="hidden"
value="yourusername">
<input name="post_return_url_approved"
type="hidden" value="<return_link_buy>">
<input name="post_return_url_declined"
type="hidden" value="<return_link_cancel>">
<input name="ID" type="hidden"
value="<order_id>">
<input name="item_qty" type="hidden"
value="1">
<input name="item_description" type="hidden"
value="<prod_name>">
<input name="item_cost" type="hidden"
value="<prod_unit_cost>">
<input name="invoice_num" type="hidden"
value="<invoice_id>">
<input type="hidden" name="bg_color"
value="#yourvalue">
<input type="hidden" name="txt_color"
value="#yourvalue">
<input type="hidden" name="company_logo"
value="yourvalue">
<input type ="SUBMIT" value="Submit">