WWW Form upload with header not working

Hi, I am trying to upload an image file from Unity where the webserver need authorisation header from authentication.

 WWWForm  form = new WWWForm();
 form.AddBinaryData("file", data, fileName, contentType);
 WWW www = new WWW(url, form);

it works fine.. But problems comes up when I use something like this even without header..

 byte[] rawData = form.data;
 WWW www = new WWW(url, rawData);

and it doesn't.. I even added some header information like this is and doesn't work either.

 Hashtable headers = new Hashtable();
 Dictionary<string, string> parameters = new Dictionary<string, string>();
 string strHeader = "something";
 headers["Authorization"] = strHeader;
 byte[] rawData = form.data;
 WWW www = new WWW(url, rawData, headers);