U812 EAI 凭证接口

hnxcy

远程调用EAI  U812凭证接口，传入xml参数格式如下：
<ufinterface roottag="voucher" billtype="voucherU8" docid="8aabe8af67d02df00167d067b3e90012" receiver="u8" sender="001" proc="add" codeexchanged="" exportneedexch="" renewproofno="true" version="2.0">
  <voucher id="8aabe8af67d02df00167d067b3e90012">
    <voucher_head>
      <company></company>
      <voucher_type>记</voucher_type>
      <fiscal_year>2018</fiscal_year>
      <accounting_period>12</accounting_period>
      <voucher_id></voucher_id>

       ........

其中接口参数中说明属性renewproofno="false"或renewproofno=""时,voucher_id（凭证号）不能为空;renewproofno="true"时,voucher_id（凭证号）可以为空，问题是我已经把renewproofno="true"了，但还是返回如下错误：

<?xml version="1.0"?><ufinterface roottag="voucheraddreturn" docid="8aabe8af67d02df00167d067b3e90012" proc="add" sender="u8" receiver="997" request-roottag="voucher"><item accounting_period="12" voucher_type="记" voucher_id="" entry_id="" succeed="1" dsc="凭证号不能为空" u8accounting_period="" u8voucher_id=""></item><item accounting_period="12" voucher_type="记" voucher_id="" entry_id="1" succeed="1" dsc="未设置对象变量或 With block 变量" u8accounting_period="" u8voucher_id=""></item><item accounting_period="12" voucher_type="记" voucher_id="" entry_id="" succeed="1" dsc="凭证分录数据有错" u8accounting_period="" u8voucher_id=""></item></ufinterface>

请问为何，U8凭证号哪里需要配置还是？