Excahnge 5.5 & IMCEXT.DLL Extension

I have implemented this to append a disclaimer to all outgoing emails. It appends to every outgoing email for anyone connecting to the exchange server through the exchange service (internal LAN) but not when connecting using Internet E-mail (pop3) over the Internet. Does anyone now of a work around so that the message gets appended automatically to all e-mails including ones sent using POP3?