Firefly over VPN

I am having a time with this one. I am trying to get firefly to show shares over VPN to some client (mac users) itunes. Here is the scinero: i have a VPN with firefly working in my server 08 box. my home dhcp is on one subnet and my vpn is on a different subnet. I don’t really need it severing my LAN. I am smart enough to use winamp. I just have some mac users that want to sample my library over VPN. I don’t see a way to change the subnet on the vpn so how do i change the subnet on firefly? THANKS!!!