How to automatically sign emails

[ml at charliesangels.biz]

Hello everyone,

I need your help. 

We do use a Strange Pearl-Script to automatically sign emails. Basically
our MTA (Exim) saves every mail to a maildir. Every mail ist then piped
to the Script. However, whenever an attachement is included, the
complete body of the email is removed.

Is there an easy way to sign mails w/o the attachement ?
I would like to use something different than the Pearl-Script we use
now.

Thanks and regards
Sascha