Leopard Server – Certificate Assistant

HI I am trying to use Certificate Assistant on Leopard server to create my own CA for signing certificates for use with the service, mail, iCal, iChat and VPN. So far I have been unable to find any good information/tutorials on the steps I need to take to achieve this. The closest I have come to finding any information on achieving my goal is here on afp548.com (https://www.afp548.com/article.php?story=20050813004038282) Unfortunately this is aimed at Tiger server and Certificate Assistant in Leopard has changed so I am not 100% that following this guide and trying to match it to what I am seeing in Certificate Assistant on Leopard is correct. The article also falls short on providing any information for configuring what is needed on the client machines. Can anyone offer some assistance in providing me with the steps I need to take to get things up and running on Leopard Server, Particularly in securing Leopard VPN using certificates for L2TP authentication rather than using a shared secret? Appreciate any help.. Steve.