如何自定义PayPal评论页面订单详细信息

I integrated PayPal Express Checkout in an auction website and to calculate the total amount of a product I have different custom parameters like auction_fee. I mapped auction_fee on PAYMENTREQUEST_0_TAXAMT in my setExpressCheckout method like below

if (isset($ec_data['tax_amount'])) {
            $tax_amount = (float)$ec_data['tax_amount'];
            $nvpstr.= "&PAYMENTREQUEST_0_TAXAMT=" . urlencode(sprintf('%.2f', $tax_amount));
        }

This gives me view like this in PayPal

But our end users mistakenly consider Tax an extra charge and we want to rename it to Auction Fee. Like this below I have gone through these links but no joys

stack1 stack2 PayPal1 PayPal2

Please suggest some solution for this.

Thanks in advance.