Update 2

Complete code listing

var request = require('request');
var cache = require('memory-cache');
var async = require('async');

var server = '172.16.221.190'
var user = 'admin'
var password ='Passw0rd'
var dn ='\\VE\\Policy\\Objects'

var jsonpayload = {"Username": user, "Password": password}


async.waterfall([
    //Get the API Key
    function(callback){
        request.post({uri: 'http://' + server +'/sdk/authorize/',
                json: jsonpayload,
                headers: {'content_type': 'application/json'}
            }, function (e, r, body) {
            callback(null, body.APIKey);
        })
},
    //List the credential objects
    function(apikey, callback){
        var jsonpayload2 = {"ObjectDN": dn, "Recursive": true}
        request.post({uri: 'http://' + server +'/sdk/Config/enumerate?apikey=' + apikey,
                json: jsonpayload2,
                headers: {'content_type': 'application/json'}
        }, function (e, r, body) {

            var dns = [];
            for (var i = 0; i < body.Objects.length; i++) {
                dns.push({'name': body.Objects[i].Name, 'dn': body.Objects[i].DN})
            }

            callback(null, dns, apikey);
        })

    },
    function(dns, apikey, callback){
      //  console.log(dns)

        var cb = [];

        for (var i = 0; i < dns.length; i++) {

        //Retrieve the credential
        var jsonpayload3 = {"CredentialPath": dns[i].dn, "Pattern": null, "Recursive": false}
            console.log(dns[i].dn)
        request.post({uri: 'http://' + server +'/sdk/credentials/retrieve?apikey=' + apikey,
            json: jsonpayload3,
            headers: {'content_type': 'application/json'}
        }, function (e, r, body) {
         //   console.log(body)
            cb.push({'cl': body.Classname})
            callback(null, cb, apikey);
            console.log(cb)
        });
        }


    }
], function (err, result) {
//    console.log(result)
    // result now equals 'done'
});    

Update:

I'm building a small application that needs to make multiple HTTP calls to a an external API and amalgamates the results into a single object or array. e.g.

1. Connect to endpoint and get auth key - pass auth key to step 2
2. Connect to endpoint using auth key and get JSON results - create an object containing summary results and pass to step 3.
3. Iterate over passed object summary results and call API for each item in the object to get detailed information for each summary line
4. Create a single JSON data structure that contains the summary and detail information.

The original question below outlines what I've tried so far!

Original Question:

Will the async.waterfall method support multiple callbacks?

i.e. Iterate over an array thats passed from a previous item in the chain, then invoke multiple http requests each of which would have their own callbacks.

e.g,

sync.waterfall([

   function(dns, key, callback){

       var cb = [];

       for (var i = 0; i < dns.length; i++) {

       //Retrieve the credential
       var jsonpayload3 = {"Cred": dns[i].DN, "Pattern": null, "Recursive": false}
           console.log(dns[i].DN)
       request.post({uri: 'http://' + vedserver +'/api/cred/retrieve?apikey=' + key,
           json: jsonpayload3,
           headers: {'content_type': 'application/json'}
       }, function (e, r, body) {
           console.log(body)
           cb.push({'cl': body.Classname})
           callback(null, cb, key);

       });
       }


   }