How to call ebay xml API from Parse cloud

I wrote code to call ebay xml API from parse cloud, but I kept getting the error saying 'Unsupported API call.The API call "GetMyeBaySellingRequest" is invalid or not supported in this release.'

I tried the same request body using ebay API's test tool(http://ift.tt/1xMkc8S), it actually works fine. The version number i used in my header is the same as the test tool.

var headers = {
            'X-EBAY-API-COMPATIBILITY-LEVEL': request.params.version,
            'X-EBAY-API-DEV-NAME' : request.params.dev_key,
            'X-EBAY-API-APP-NAME': request.params.app_key,
            'X-EBAY-API-CERT-NAME': request.params.cert_key,
            'X-EBAY-API-CALL-NAME': request.params.call_name,
            'X-EBAY-API-SITEID' : "0",
            'Content-Type': 'text/xml'
        };
Parse.Cloud.httpRequest({
        method: 'POST',
        url: request.params.url,
        headers: headers,
        body: request.params.request_body,
        success: function(httpResponse) {
            console.log(httpResponse.text);
            response.success(httpResponse.text);
        },
        error: function(httpResponse) {
            console.error('Request failed with response code ' + httpResponse.status);
            response.error('Request failed with response code ' + httpResponse.status);
        }
    });

Please help. Thanks.