PPTP VPN WAN listening address

From:	Robert Goodyear <me at jrob dot net>
To:	m0n0wall at lists dot m0n0 dot ch
Subject:	PPTP VPN WAN listening address
Date:	Sun, 11 Mar 2007 22:57:12 -0700

Can anyone tell me how to instruct m0n0's PPTP VPN to listen to a  
specific WAN address other than the first address in my WAN subnet?

Thanks!
-Rob.