When I originally wrote the howto you are looking for here (several years ago), my circumstances were very different from what they are now. For better or worse, that's changed, and I neither have access to IPCop anymore nor the time to properly maintain this resource. I do get occasional requests to update the information contained herein, and wish I could help in some way.
What I propose to do is this: I'm making the entire HOWTO available for anyone who wants to have a copy here, with the explicit declaration that you can use it for however you want, but that you, the downloader, understand that the information is out of date. If someone wants to download it, update the information, and maintain it, great. If they want to take full credit for the entire work, they'll have to live with themselves, but I don't much mind.
I appreciate all the compliments and suggestions people have sent me over the years, and am very glad to know that IPCop is still being used - it's truly a fantastic community-built, 100% free toolkit, and I wouldn't hesitate to recommend it to anyone. To you, for example. And I'm quite sure that getting the equally-excellent IPSecuritas to work with IPCop can still work with a few changes from my old guide. But I'm not comfortable leaving outdated information up any longer - it wastes people's time to think they found the definitive guide, only to realize that the software nowadays looks completely different.
I wish you the best, and feel free as always to email comments to vpnpage at this domain.