Authentication and header rejection with Twitpic and OAuth

[Killer04]

I am trying my best to upload images to Twitpic by using PHP and OAuth (PECL extension) and I keep getting the following error:\[quote\] Could not authenticate you (header rejected by twitter)\[/quote\]This is my code so far:\[code\]$arguments[] = "oauth_consumer_key=" . $this->consumer_key;$arguments[] = "oauth_nonce=" . md5(time());$arguments[] = "oauth_signature_method=HMAC-SHA1";$arguments[] = "oauth_timestamp=" . time();$arguments[] = "oauth_token=" . $this->oauth_token;$arguments[] = "oauth_version=1.0";$sbs = oauth_get_sbs("POST", "http://api.twitpic.com/2/upload.xml", $arguments);$signature = urlencode(base64_encode(hash_hmac("sha1", $sbs, $this->consumer_secret . "&", true)));$arguments[] = "oauth_signature=" . $signature;sort($arguments);$headers[] = "X-Auth-Service-Provider: http://api.twitter.com/1/account/verify_credentials.json";$headers[] = "X-Verify-Credentials-Authorization: OAuth\n" . implode(",\n", $arguments);$postfields["key"] = $this->api_key;$postfields["media"] = "@$image";$postfields["message"] = $message;$curl = curl_init();curl_setopt($curl, CURLOPT_URL, "http://api.twitpic.com/2/upload.xml");curl_setopt($curl, CURLOPT_POST, true);curl_setopt($curl, CURLOPT_POSTFIELDS, $postfields);curl_setopt($curl, CURLOPT_HTTPHEADER, $headers);curl_setopt($curl, CURLOPT_VERBOSE, true);curl_setopt($curl, CURLOPT_HEADER, true);curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);echo curl_exec($curl);\[/code\]Can someone tell me what am I doing wrong?