Curl

curl_easy_setopt(curl, CURLOPT_RESUME_FROM, downloadedSz);
mywxCurlHttpObject->SetOpt(CURLOPT_FOLLOWLOCATION, 1);

А также

myHTTP http(wxT("http://www.188bet.com/en/default.aspx"));
http.SetOpt(CURLOPT_HEADER,true);
http.SetOpt(CURLOPT_SSL_VERIFYHOST,false);
http.SetOpt(CURLOPT_TIMEOUT,20);
http.SetVerbose(true);
http.Headers();