How to download remote pdf

[flexdev]

Hello,
I have to create a unigui application that has to download pdf files generated by another unigui application sent via unisession.sendfile (which runs on a different server).
If I try to download them directly from the browser I get the correct pdf files, if I try to download them via:
var
  IdHTTP1: TIdHTTP;
  Stream: TMemoryStream;
  Url, FileName: String;
begin
  Url: = 'http://192.168.69.116:8077?callback=PDF';
  Filename: = 'download.pdf';

  IdHTTP1: = TIdHTTP.Create (Self);
  Stream: = TMemoryStream.Create;
  try
    IdHTTP1.Get (Url, Stream);
    Stream.position: = 0;
    Stream.SaveToFile (FileName);

  finally
    Stream.Free;
    IdHTTP1.Free;
  end;
i get not the pdf but a text file.
Where am I doing wrong?

Thank's in advance.