.wmz message attachments

I have a problem with a user on my network. When they send e-mails the recipients receive the mails with various .wmz attachments. We run Exchange server 2003 and outlook 2003. The user sends mails in HTML format but without anything other than text in the body of the e-mail. Any pictures etc are sent as attachments. The signiture is also rich text with no graphics.
Is there anyway of removing these attachments?? If anyone else has had this problem I’d be interested to hear from them.
Cheers Rob