How to send a correct authorization header for basic authentication

I am trying to POST data from my API but I can't pass the basic authentication.

I try:

$.ajax({
  type: 'POST',
  url: http://theappurl.com/api/v1/method/,
  data: {},
  crossDomain: true,
  beforeSend: function(xhr) {
    xhr.setRequestHeader('Authorization', 'Basic [REDACTED]');
  }
});

My server configuration response is:

response["Access-Control-Allow-Origin"] = "*"
response["Access-Control-Allow-Methods"] = "POST"
response["Access-Control-Max-Age"] = "1000"
response["Access-Control-Allow-Headers"] = "*"

The headers that I get is:

Request Headers

OPTIONS /api/v1/token-auth/ HTTP/1.1
Host: theappurl.com
Connection: keep-alive
Access-Control-Request-Method: POST
Origin: http://127.0.0.1:8080
User-Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.31 (KHTML, like Gecko) Chrome/26.0.1410.63 Safari/537.31
Access-Control-Request-Headers: origin, authorization, content-type
Accept: */*
Referer: http://127.0.0.1:8080/
Accept-Encoding: gzip,deflate,sdch
Accept-Language: es,en;q=0.8
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3

Response header

HTTP/1.1 401 Unauthorized
Server: nginx/1.1.19
Date: Fri, 16 Aug 2013 01:29:21 GMT
Content-Type: text/html
Content-Length: 597
Connection: keep-alive
WWW-Authenticate: Basic realm="Restricted"

I guess the server configuration is good because I can access to API from the Advanced REST Client (Chrome Extension)

Any suggestions?

PD: The header that I get from Advanced REST client is:

    User-Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.31 (KHTML, like Gecko) Chrome/26.0.1410.63 Safari/537.31
    Origin: chrome-extension://hgmloofddffdnphfgcellkdfbfbjeloo
    Authorization: Basic [REDACTED]
    Content-Type: application/x-www-form-urlencoded 
    Accept: */*
    Accept-Encoding: gzip,deflate,sdch
    Accept-Language: es,en;q=0.8
    Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3

and

    Server: nginx/1.1.19 
    Date: Fri, 16 Aug 2013 01:07:18 GMT 
    Content-Type: application/json; charset=utf-8 
    Transfer-Encoding: chunked 
    Connection: keep-alive
    Vary: Accept, Cookie 
    Allow: POST, OPTIONS 
    X-Robots-Tag: noindex

sending OPTION method

Important: This answer is out-of-date. While this answer may have worked for a particular case in 2013, users and passwords in the URL are now deprecated according to Mozilla and RFC 3986.

---

You can include the user and password as part of the URL:

http://user:passwd@www.server.com/index.html

see this URL, for more

HTTP Basic Authentication credentials passed in URL and encryption

of course, you'll need the username password, it's not 'Basic hashstring.