Build Dynamic message footer in Exchange 2007

Hello,

Is there a way to modify all outgoing messages from Exchange server 2007 to include an Unsubscribe link that would have the outgoing message's subject and sender in the body?

Here's what I had in mind...

<a href="mailto:yourlist@yourdomain?subject=Unsubscribe&body='Original Sender was ' + %%Sender%% ' and Subject was ' + %%Subject%%">Unsubscribe Me</a>

Lukasz