[Setup]
AppName=My Program
AppVersion=1.5
DefaultDirName={pf}\My Program

[Code]
procedure InitializeWizard;
begin
  // just tell the plugin when we want to start
  idpDownloadAfter(wpReady);
end;

procedure CurPageChanged(CurPageID: Integer);
begin
  // if the user just reached the ready page, then...
  if CurPageID = wpReady then
  begin
    // because the user can move back and forth in the wizard, this place can
    // be executed multiple times, so we need to clear the file list first
    idpClearFiles;
    // and add the files to the list; at this time, the {app} directory is known
    idpAddFileComp('ftp://user:pass@server.xy/folder/myFile1.exe', ExpandConstant('{app}\subfolder\Download\myFile1.exe'), 'dl\aaa');
    idpAddFileComp('ftp://user:pass@server.xy/folder/myFile2.exe', ExpandConstant('{app}\subfolder\Download\myFile2.exe'), 'dl\bbb');
    idpAddFileComp('ftp://user:pass@server.xy/folder/myFile3.exe', ExpandConstant('{app}\subfolder\Download\myFile3.exe'), 'dl\ccc');
  end;
end;