I have been playing with a vanilla version of OpenLDAP (the latest version) and I have managed to get the schema to import fine. However even that wasn't a very straight forward process with the new version of LDAP the way you import things is done slightly differently and how you authenticate is done slightly differently too.
So I have come back to give UCS one last try before I just abandon it and use Apache Directory Studio to manage a vanilla version.
If there wasn't a limitation posed on the number of extended attributes UCS allows it would be worth spending the time on to make it work, however as I have to make several applications authenticate with it, the likelihood that I will run out is high, and makes it a limiting factor going forward when the system is expanded further.
If you get chance to post your steps you took, it would be interesting for the future as UCS might be usable for other projects, unfortunately for this one it is looking unusable.