uniCloud.httpProxyForEip.post请求如何带上证书

uniCloud.httpclient.request请求时，可以带上证书

uniCloud.httpclient.request(  
      ‘https://api.mch.weixin.qq.com/mmpaymkttransfers/sendminiprogramhb’,  
      {  
        method: "POST",  
        data: data,  
        headers: {  
          "Content-Type": "application/xml"  
        },  
        dataType: 'text',  
        cert: mp.appCertPath,  
        key: mp.appPrivateKeyPath,  
      }  
    );

uniCloud.httpProxyForEip.post请求没有证书的入参，请问如何能够带上证书