Can IP Masquerading Handle L2TP Connections?

carrier lost asks: "I have to connect to my company's VPN using L2TP. I am masquerading my company-provided Windows boxes behind Linux 2.2.16. I have successfully configured the combination to provide PPTP, but now I have to figure out how to enable L2TP. Has anyone done this? Can you point me to a step-by-step tutorial?"