' Пытаюсь писать файл на сервер (пишу через HTTP-прокси)
Public Declare Function HttpSendRequestEx Lib "wininet.dll" Alias "HttpSendRequestExA" ( _
                ByVal hRequest As Long, ByRef lpBuffersIn As INTERNET_BUFFERS, _
                ByRef lpBuffersOut As INTERNET_BUFFERS, _
                ByVal dwFlags As Long, ByVal dwContext As Long) As Long
... 'Открываю запрос
hReq = HttpOpenRequest(hConnection, "POST", strURL, vbNullString, vbNullString, _
                                    0 &, INTERNET_FLAG_NO_CACHE_WRITE,  0 )
'    Отправляю запрос
iReq = HttpSendRequest(hReq, vbNullString,  0 , vbNullString,  0 )
'    Читаю файл в текстовую переменную
Open "c:\text.ext" For Binary Access Read As # 71 : fLen = LOF( 71 ): sFile = InputB(fLen, # 71 )
Close # 71 
'    Заполняю структуру (изъято из примера на С++)
    BufferIn.dwStructSize = Len(BufferIn)   '; // Must be set or error will occur
    BufferIn.Next =  0 & 'Null ';
    BufferIn.lpcszHeader =  0 & 'Null ';
    BufferIn.dwHeadersLength =  0  ';
    BufferIn.dwHeadersTotal =  0  ';
    BufferIn.lpvBuffer =  0 & 'Null ';
    BufferIn.dwBufferLength =  0  ';
    BufferIn.dwBufferTotal = fLen '; // This is the only member used other than dwStructSize
    BufferIn.dwOffsetLow =  0  ';
    BufferIn.dwOffsetHigh =  0  ';
 '   Отправляю расширение запроса
LRet = HttpSendRequestEx(hReq, BufferIn, BufferOut,  0 ,  0 ) 'Null, 0, 0)
'  Пишу файл пакетами по 2К 
i =  0 
Do
    i = i +  1 :   pos =  2048  * (i -  1 ) +  1 
    If fLen - pos >  2048  Then sBuffer = Mid(sFile, pos,  2048 ) Else sBuffer = Mid(sFile, pos)
    iRet = InternetWriteFile(hReq, sBuffer, Len(sBuffer), dwBytesWritten)
    If iRet =  0  Then
        ErrorOut Err.LastDllError, "InternetWriteFile"
        GoTo  89 
    End If
    If Not fLen - pos >  2048  Then Exit Do
Loop

Dim dBuffer As Long, pBuffer() As Byte
dBuffer =  2048 : ReDim pBuffer( 1  To dBuffer)
'...
    Get # 71 , , pBuffer
    iRet = InternetWriteFile(hReq, pBuffer( 1 ), dBuffer, dwBytesWritten)

LRet = HttpSendRequestEx(hReq, BufferIn,  0 ,  0 ,  0 )