my $resp = $ua->request(
  # ZUWEISEN
  POST         => 'http://192.168.0.248/cfg.html',
  Content_Type => 'form-data',
  'SID'        => 'xy00',
  'id'         => '56069145',
  'file'       => ["C:\Dokumente und Einstellungen\user\Desktop\myConfigFile.xml"]
);