Here are some useful links when working with AS/2 in BizTalk:
Configuration chart for AS2 in BizTalk 2006 R2
http://blogs.msdn.com/biztalkb2b/archive/2007/05/30/as-2-certificate-management.aspx
In depth explanation of SSL security
http://en.wikipedia.org/wiki/Transport_Layer_Security
Win32 version of openSSL
http://www.slproweb.com/products/Win32OpenSSL.html
Step by Step instructions for creating the certificates andadding them to the Windows Certificate store