Case C-230/06: Judgment of the Court (Third Chamber) of 3 April 2008 (reference for a preliminary ruling from the Corte Suprema di Cassazione (Italy), Militzer & Münch GmbH v Ministero delle Finanze (Customs union — Community transit — Recovery of a customs debt — Competent Member State — Proof of the regularity of the operation or of the place of the offence — Time-limits — Liability of the principal)