Modifying attachments   

Hi,
 I would like for specific list of destination addresses modify the message 
attachments, like converting Office Open XML files into older binary format. 
How can I touch the attachments? Running Exchange 2003 SP2 on Win SBS R2, 
clients using MAPI (Outlook 2007).

        Thanks for any idea,
           Jan

date: Sat, 24 Feb 2007 18:12:48 +0100   author:   Jan Kucera am