NAT-T in OSX so I can use OpenSWAN+L2TP to build my VPN?

Per this page: http://www.jacco2.dds.nl/networking/freeswan-panther.html#NAT-Traversal OSX doesn't support NAT-T ... :( Is there a way to use natd under OSX (or something?!) to get around this problem? I really want to get my VPN up and running using OpenSWAN on Linux, and using the built-in VPN clients of OSX, but this appears to be a bit of a show-stopper for me ... Anyone got any clues, otherwise, how to use a Linux box to build a VPN that will allow Windows2000 clients and OSX clients (road warriors) to connect and share a VPN together? I'm really tearing my hair out here ...