How to specify xsi:type for an element in SOAP request using node-soap

I'm trying to call the Create method passing in a TriggeredSend typed object named Objects to an ExactTarget SOAP Web Service using the node-soap package.

I need to create something that looked like this (note the xsi:type="ns0:TriggeredSend"):

<SOAP-ENV:Envelope xmlns:etns="http://exacttarget.com" xmlns:wsse="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd" xmlns:ns0="http://exacttarget.com/wsdl/partnerAPI" xmlns:ns1="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/">
   <SOAP-ENV:Header>
   </SOAP-ENV:Header>
   <ns1:Body>
      <ns0:CreateRequest>
         <ns0:Objects xsi:type="ns0:TriggeredSend">
            <ns0:TriggeredSendDefinition>
               <ns0:CustomerKey>abc</ns0:CustomerKey>
            </ns0:TriggeredSendDefinition>
         </ns0:Objects>
      </ns0:CreateRequest>
   </ns1:Body>
</SOAP-ENV:Envelope>

With the code below I get close:

var soap = require('soap')

soap.createClient(url, function(err, client){
    client.Create({
        Objects: {
            TriggeredSendDefinition: {
                CustomerKey: 'abc'
            }
        },
        function(err, response) {})
    });
});

Which gives me this (without the xsi:type):

<ns0:CreateRequest>
   <ns0:Objects>
     <ns0:TriggeredSendDefinition>
        <ns0:CustomerKey>abc</ns0:CustomerKey>
     </ns0:TriggeredSendDefinition>
  </ns0:Objects>
</ns0:CreateRequest>

How do I specify the TriggeredSend type for the Objects element?

There is a special attributes node you can add to specify the xsi:type:

var soap = require('soap')

soap.createClient(url, function(err, client){
    client.Create({
        Objects: {
            attributes: {
                xsi_type: {
                    type: 'TriggeredSend',
                    xmlns: 'http://exacttarget.com/wsdl/partnerAPI'
                }
            }
            TriggeredSendDefinition: {
                CustomerKey: 'abc'
            }
        },
        function(err, response) {})
    });
});

Which produces:

<ns0:CreateRequest>
   <ns0:Objects xsi:type="ns0:TriggeredSend">
      <ns0:TriggeredSendDefinition>
         <ns0:CustomerKey>abc</ns0:CustomerKey>
      </ns0:TriggeredSendDefinition>
   </ns0:Objects>
</ns0:CreateRequest>