[otrs] How to set date header in otrs mail ?

Hi all, As anyone have an idea how to set date header in mail sent by otrs ? My SMTP server (I don't have acces to it) don't put date header in sent mail. Is it possible to set it by otrs ? I try to modifiy SMTP.pm to put date header but without results. As anyone have an idea ? Thanks in advance for your help -- Guillaume REHM Service Informatique Bibliothèque Nationale et Universitaire de Strasbourg 5 rue du Maréchal Joffre BP 51029 67070 Strasbourg tél: 03 88 25 28 43 fax: 03 88 25 28 03 mail: guillaume.rehm@bnu.fr web: http://www.bnu.fr