CString strHeader(TEXT("Content-Type: application/x-www-form-urlencoded; text/html;charset=windows-1251"));
CString strPOST(TEXT("qqq=www"));

::HttpSendRequest(
hRequest,
(LPCTSTR)strHeader,
strHeader.GetLength(),
(LPVOID)(LPCTSTR)strPOST,
strPOST.GetLength());