How do I upload an NSImage(NSData)to Twitpic with OAMutableURLRequest?

Question

I'm using OAConsumer in my xAuth twitterEngine and i'm adding Twitpic OAuth Echo to it. But it won't POST the NSData. here is some of my code:

//other file



NSArray *reps = [[imageToUpload image] representations];
  NSData *imageData = [NSBitmapImageRep representationOfImageRepsInArray:reps 
                             usingType:NSJPEGFileType
                            properties:nil];
  [twitter testUploadImageData:imageData withMessage:@"Hello WORLD!!" toURL:[NSURL URLWithString:uploadURL.stringValue]];

            //

- (void)testUploadImageData:(NSData *)data withMessage:(NSString *)message toURL:(NSURL *)url;
            {
        //url = @"http://api.twitpic.com/2/upload.xml"
        //message = @"Hello WORLD!!"

             NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];  
             NSString *String = [[NSString alloc] initWithData:data encoding:NSASCIIStringEncoding];
         NSLog(@"dataString: %@",String);
         OAMutableURLRequest *request = [[OAMutableURLRequest alloc] initWithURL:url
                           consumer:self.consumer
                           token:_accessToken
                           realm:nil
                        signatureProvider:nil];

         // Setup POST body
         [request setHTTPMethod:@"POST"];
         //NSString *stringBoundary = [NSString stringWithString:@"0xKhTmLbOuNdArY"];
            //NSString *contentType = [NSString stringWithFormat:@"multipart/form-data; boundary=%@", stringBoundary];
         //   NSString *stringBoundarySeparator = [NSString stringWithFormat:@"\r\n--%@\r\n", stringBoundary];
         /*

            NSMutableString *postString = [NSMutableString string];
            [postString appendString:@"\r\n"];
            [postString appendString:stringBoundarySeparator];
            [postString appendString:[NSString stringWithFormat:@"Content-Disposition: form-data; name=\"message\"\r\n\r\n%@", message]];
            [postString appendString:stringBoundarySeparator];
            [postString appendString:[NSString stringWithFormat:@"Content-Disposition: form-data; name=\"media\"; filename=\"%@\"\r\n", @"file.jpg"]];
            [postString appendString:@"Content-Type: image/jpg\r\n"];
            [postString appendString:@"Content-Transfer-Encoding: binary\r\n\r\n"];

            // Setting up the POST request's multipart/form-data body
            NSMutableData *postBody = [NSMutableData data];
            [postBody appendData:[postString dataUsingEncoding:NSUTF8StringEncoding]];
            [postBody appendData:data];

         [request setHTTPBody:postBody];
          */
         [request setHTTPMethod:@"POST"];
         NSString *thing = [[NSString alloc] initWithData:data encoding:NSASCIIStringEncoding];
         NSLog(@"%@",thing);

         [request setParameters:[NSArray arrayWithObjects:
               [OARequestParameter requestParameterWithName:@"oauth_token" value:_accessToken.key],
               [OARequestParameter requestParameterWithName:@"X-Auth-Service-Provider" value:@"https://api.twitter.com/1/account/verify_credentials.json"],
               [OARequestParameter requestParameterWithName:@"key" value:@"my-key-here :P"],
               [OARequestParameter requestParameterWithName:@"message" value:message],
        //iv'e changed this many times. I was just trying this to see if it works
               [OARequestParameter requestParameterWithName:@"media" value:thing],
               nil]];
         OAAsynchronousDataFetcher *dataFetcher = [[OAAsynchronousDataFetcher alloc] init];
         [dataFetcher initWithRequest:request delegate:self 
              didFinishSelector:@selector(uploadDidUpload:withData:) 
             didFailSelector:@selector(uploadDidFail:withData:)];
         [dataFetcher start];
         [dataFetcher release];
         [request release];
         [pool drain];
}

I'm authenticated but it still won't POST the data :(