uploader un fichier par FTP en DOS via un Proxy

Bonjour,
J'ai utilisé le programme ftp de DOS de Windows pour envoyer un fichier chaque jour avec Vbscript. Nous venons d'ajouter un serveur SQUID proxy dans notre réseau avec un Login et un Mot de passe utilisant le port 3128.
Ma question est la suivante: comment faire pour modifier cette Fonction Ftpupload pour résoudre ce probléme de Proxy?
Merci d'avance!
'-------------------FTPUPLOAD----------------------
Function FTPUpload(sSite, sUsername, sPassword, sLocalFile, sRemotePath)
'This script is provided under the Creative Commons license located
'at http://creativecommons.org/licenses/by-nc/2.5/ . It may not
'be used for commercial purposes with out the expressed written consent
'of NateRice.com

Const OpenAsDefault = -2
Const FailIfNotExist = 0
Const ForReading = 1
Const ForWriting = 2

Set oFTPScriptFSO = CreateObject("Scripting.FileSystemObject")
Set oFTPScriptShell = CreateObject("WScript.Shell")

sRemotePath = Trim(sRemotePath)
sLocalFile = Trim(sLocalFile)

'----------Path Checks---------
'Here we willcheck the path, if it contains
'spaces then we need to add quotes to ensure
'it parses correctly.
If InStr(sRemotePath, " ") > 0 Then
If Left(sRemotePath, 1) <> """" And Right(sRemotePath, 1) <> """" Then
sRemotePath = """" & sRemotePath & """"
End If
End If

If InStr(sLocalFile, " ") > 0 Then
If Left(sLocalFile, 1) <> """" And Right(sLocalFile, 1) <> """" Then
sLocalFile = """" & sLocalFile & """"
End If
End If

'Check to ensure that a remote path was
'passed. If it's blank then pass a "\"
If Len(sRemotePath) = 0 Then
'Please note that no premptive checking of the
'remote path is done. If it does not exist for some
'reason. Unexpected results may occur.
sRemotePath = "\"
End If

'Check the local path and file to ensure
'that either the a file that exists was
'passed or a wildcard was passed.
If InStr(sLocalFile, "*") Then
If InStr(sLocalFile, " ") Then
FTPUpload = "Error: Wildcard uploads do not work if the path contains a " & _
"space." & vbCRLF
FTPUpload = FTPUpload & "This is a limitation of the Microsoft FTP client."
Exit Function
End If
ElseIf Len(sLocalFile) = 0 Or Not oFTPScriptFSO.FileExists(sLocalFile) Then
'nothing to upload
FTPUpload = "Error: File Not Found."
Exit Function
End If
'--------END Path Checks---------

'build input file for ftp command
sFTPScript = sFTPScript & "USER " & sUsername & vbCRLF
sFTPScript = sFTPScript & sPassword & vbCRLF
sFTPScript = sFTPScript & "cd " & sRemotePath & vbCRLF
sFTPScript = sFTPScript & "binary" & vbCRLF
sFTPScript = sFTPScript & "prompt n" & vbCRLF
sFTPScript = sFTPScript & "put " & sLocalFile & vbCRLF
sFTPScript = sFTPScript & "quit" & vbCRLF & "quit" & vbCRLF & "quit" & vbCRLF


sFTPTemp = oFTPScriptShell.ExpandEnvironmentStrings("%TEMP%")
sFTPTempFile = sFTPTemp & "\" & oFTPScriptFSO.GetTempName
sFTPResults = sFTPTemp & "\" & oFTPScriptFSO.GetTempName

'Write the input file for the ftp command
'to a temporary file.
Set fFTPScript = oFTPScriptFSO.CreateTextFile(sFTPTempFile, True)
fFTPScript.WriteLine(sFTPScript)
fFTPScript.Close
Set fFTPScript = Nothing

oFTPScriptShell.Run "%comspec% /c FTP -n -s:" & sFTPTempFile & " " & sSite & _
" > " & sFTPResults, 0, TRUE

Wscript.Sleep 1000

'Check results of transfer.
Set fFTPResults = oFTPScriptFSO.OpenTextFile(sFTPResults, ForReading, _
FailIfNotExist, OpenAsDefault)
sResults = fFTPResults.ReadAll
fFTPResults.Close

oFTPScriptFSO.DeleteFile(sFTPTempFile)
oFTPScriptFSO.DeleteFile (sFTPResults)

If InStr(sResults, "226 Transfer complete.") > 0 Then
FTPUpload = True
ElseIf InStr(sResults, "File not found") > 0 Then
FTPUpload = "Error: File Not Found"
ElseIf InStr(sResults, "cannot log in.") > 0 Then
FTPUpload = "Error: Login Failed."
Else
FTPUpload = "Error: Unknown."
End If

Set oFTPScriptFSO = Nothing
Set oFTPScriptShell = Nothing
End Function