Why 12, in recent days.. I was involved with a similar project where we had to migrate from ossn to unacms.. but we migrate straight to the current version we were using... The only challenge we had or consideration was the fact that unacms uses SHA-1 password encryption whereas ossn used MD5 hashing. and we wanted to move the users across. We used a script, but had to in the end let the users be directed to password reset to avoid further complication, other than that, go for RC5.. I think the patches are released and fixed most of the problems... and might just fix the one you currently have.