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 :(