Microsoft VPN is PPTP protocol using TCP port 1723 and protocol GRE.
Make sure you static translate the w2k server from DMZ to outside public ip address and open those ports.
x.x.x.x is the translated ip address (public) , y.y.y.y is the W2k server in the DMZ.
static (dmz, outside) x.x.x.x y.y.y.y
conduit permit tcp host x.x.x.x eq 1723 any
conduit permit gre host x.x.x.x any
Best Regards,