Accessing Azure storage from Windows Phone with REST

Question

I'm struggling in the attempt to establish a simple httpwebrequest to gather some metadata on a blob,
my code works perfectly fine on windows but
gives error 403 on windows phone 7.
The really strange thing is that as you can see from the HEAD requests
the same auth that is ok from windows is not ok on windows phone...
I use a standard httpwebrequest to establish the connection, the code is at the end of the post.
I lost already 10 hours attempting anything that made sense to me, but with no success at all:
i ended up establishing a Fiddler tunnel connection to compare the requests,
WORKING : Windows 8.1 desktop executable
HEAD https://{MYHOST}.blob.core.windows.net/add-saves/save{etc...} HTTP/1.1
ContentLength: 0
x-ms-date: Thu, 05 Feb 2015 00:50:00 GMT
x-ms-version: 2009-09-19
Authorization: SharedKey heartbit:YnZwcEoRunuuoK6PC+JRge{etc...}
Host: {MYHOST}.blob.core.windows.net
RETURNS
HTTP/1.1 200 OK
Content-Length: 21648
Content-Type: application/octet-stream
Last-Modified: Wed, 04 Feb 2015 21:19:07 GMT
ETag: 0x8D20ED7587824FE
Server: Windows-Azure-Blob/1.0 Microsoft-HTTPAPI/2.0
x-ms-request-id: 767e3faa-0001-0016-1559-eb76ed000000
x-ms-version: 2009-09-19
x-ms-lease-status: unlocked
x-ms-blob-type: BlockBlob
Date: Thu, 05 Feb 2015 00:54:41 GMT
and my Windows Phone 7 app (throws with WebResponse 404 NotFound from webserver)
HEAD https://{MYHOST}.blob.core.windows.net/add-saves/save{etc...} HTTP/1.1
Accept: */*
Accept-Encoding: identity
ContentLength: 0
x-ms-date: Thu, 05 Feb 2015 00:50:00 GMT
x-ms-version: 2009-09-19
Authorization: SharedKey heartbit:YnZwcEoRunuuoK6PC+JRge{etc...}
Referer: file:///Applications/Install/5FEE5BAA-57A1-4451-B4A5-28E2E46C5598/Install/
User-Agent: NativeHost
Host: {MYHOST}.blob.core.windows.net
Content-Length: 0
Connection: Keep-Alive
Cache-Control: no-cache
RETURNS
HTTP/1.1 403 Server failed to authenticate the request. Make sure the value of Authorization header is formed correctly including the signature.
Transfer-Encoding: chunked
Server: Microsoft-HTTPAPI/2.0
x-ms-request-id: b2654a03-0001-0038-1dd9-c4cb58000000
Date: Thu, 05 Feb 2015 00:55:00 GMT
byte[] byteArray = null;
// There is an error where on the android system the clock could be set ahead in time when the request is made to when it arrives to ms's servers
// Giving a minute of backlogging could be enough
DateTime now = DateTime.UtcNow - TimeSpan.FromMinutes(1);
string uri = Endpoint + resource;
HttpWebRequest request = CreateRequestBody(method, requestBody, headers, ref byteArray, now, uri);
string messageSign = MessageSignature(method, now, request, ifMatch, md5);
requestAuthAsync(messageSign, authKey =>
try
if (((string)authKey) == "Error")
throw new Exception("Auth failure");
String AuthorizationHeader = "SharedKey " + StorageAccount + ":" + authKey;
request.Headers.Add("Authorization", AuthorizationHeader);
if (!String.IsNullOrEmpty(requestBody))
request.GetRequestStream().Write(byteArray, 0, byteArray.Length);
request.BeginGetResponse((ar) =>
try
var r = request.EndGetResponse(ar);
onCompleted(r);
catch (WebException e)
onCompleted.Invoke("Error : " + (e.Response as HttpWebResponse).StatusDescription);
catch (Exception e)
onCompleted.Invoke("Error : " + e.Message);
}, null);
catch (Exception e)
onCompleted.Invoke("Error : " + e.Message);
catch(Exception ioe)
onCompleted.Invoke("Error : " + ioe.Message);
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Answer 1

It seems like thw windows phone version of HttpWebRequest automatically adds a "Content-Length" header that is different from the one given by me ("ContentLength"). Why is that?
The auth signing shouldnt depend on that right?
Since i cannot find a way to remove that header i tried removing the one i was manually adding, but without luck.
Are the other headers that are  automatically added on windows phone :
Accept: */*
Accept-Encoding: identity
Referer: file:///Applications/Install/5FEE5BAA-57A1-4451-B4A5-28E2E46C5598/Install/
User-Agent: NativeHost
Content-Length: 0
Connection: Keep-Alive
Cache-Control: no-cache
Will they create issues with autorization? The auth string in WP is the same found on Windows so there must be something in the WP request to azure that doesn't match the auth string i generated early.
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