Sauvegarde de stream dans un .csv, .xls...

Réponse acceptée !
Salut!
En fait j'ai tout simplement recopié bit à bit le stream dans un filestream local.

Stream stream = REPONSE DU SERVER;
byte[] bytesTab = ReadFully(stream, 0);
FileStream s = new FileStream(fileName, FileMode.Create);
foreach (byte b in bytesTab)
{
      s.WriteByte(b);
 }
     s.Close();

public static byte[] ReadFully(System.IO.Stream stream, int initialLength)
        {
          
            if (initialLength < 1)
            {
                initialLength = 32768;
            }

            byte[] buffer = new byte[initialLength];
            int read = 0;

            int chunk;
            while ((chunk = stream.Read(buffer, read, buffer.Length - read)) > 0)
            {
                read += chunk;

              
                if (read == buffer.Length)
                {
                    int nextByte = stream.ReadByte();

                    // End of stream? If so, we're done
                    if (nextByte == -1)
                    {
                        return buffer;
                    }

                  
                    byte[] newBuffer = new byte[buffer.Length * 2];
                    Array.Copy(buffer, newBuffer, buffer.Length);
                    newBuffer[read] = (byte)nextByte;
                    buffer = newBuffer;
                    read++;
                }
            }
          
            byte[] ret = new byte[read];
            Array.Copy(buffer, ret, read);
            return ret;
        }

Voili voilou.
Je recupere tout type de format comme ca: csv, xls, zip etc.
:)