[Mailman-Users] Banner and Complex code in header and footer

[Ulisse]

At the moment i can insert, such as header and footer, in the messages sent via Mailman Mailing lists only pure text and links. Is it possible, for the administrator/moderator of the lists, to insert images, html code, banner, java feed or other complex code, such as header and footer, in every message sent via Mailman Mailing lists ??? 
If yes. If it is possible... What is the system ??? Have you some instructions ? A link ? Exist an rpm or a modification ???