Getting Access Key for OAuth 2.0 Authentication

I'm a new comer studying server communication with Unity 4.5

I have been following a OAuth 2.0 guide(Pic. below) provided from the server I want to communicate with.

And with communication tutorial(http://unity-tutorials.blogspot.ca/), tried to follow the guide using WWW in Javascript.

But the guide is too ambiguous to me, 2 headers? 1 Body? How do I specify them in the WWWForm? I tried simply modifying the values in AddField portion of the tutorial but it gave me an error:

Error: Rejected because no crossdomain.xml policy file was found
UnityEngine.Debug:Log(Object)
$:MoveNext() (at Assets/Scripts/StartMenu/LoginService.js:27)

The portion of code modified from the tutorial:

Code (JavaScript):

1. public function sendLoginData(loginData : LoginData, responseHandler) {
2.      
3.         var response : Response = new Response();
4.      
5.         Debug.Log("Sending login request to " + LOGIN_URL);
6.      
7.         // Creating form with login and password fields to send using POST method:
8.         var loginForm = new WWWForm();
9.  
10.         [COLOR=#000000]loginForm.AddField("Authorization","eDJlcFpCNzRTOXFxMnBTdxT3Z2dzo1aVNmbW1PTzUyUG12N0N3");
11.         loginForm.AddField("Content-Type", "application/xwwwformurlencoded");
12.         loginForm.AddField("BODY", "grant_type=client_credentials");[/COLOR]
13.  
14.         // Sending request:
15.         var httpResponse = new WWW(LOGIN_URL, loginForm);
16.  
17.         // Waiting for response:
18.         yield httpResponse;

I've been googling and searching in forum for answers, but I couldn't find (or understand) how to properly do this. It just made me realize it's not simple as I hoped.

 

I came across this post a bunch when I was trying to figure out how to do oauth in unity. Finally figured it out myself so now I'm going and sharing my results in a post I made.

http://technicalartistry.blogspot.be/2015/07/oauth2-unity-and-month-of-cursing.html?m=1

Give it a look and hope it helps.

EDIT:
For those that come after me, There is also this new blogpost about doing OAuth in Unity for Android WITHOUT a webview (so free )
http://technicalartistry.blogspot.ca/2016/01/fitbit-unity-oauth-2-and-native.html