Samba, OX, Squid, etc.. with LDAP backend

Hello List,

I set up a samba pdc with ldap, smbldap-tools about one year ago.

Now i would like to extend it with OpenXchange, squid, etc...

Has someone got ubuntu running with samba and OpenXchange on a LDAP backend?

After checking out the LDAP Directory tree i was wondering what the 
Organisation Units "DSA" and "ldmap" are good for?

My current tree looks like this:

dc=example,dc=com
+ ou=Computers
+ ou=DSA
+ ou=Groups
+ ou=Idmap
+ ou=Users
+ sambaDomainName=MyDomain



I also had a look at Collax PDC and they even have an additional 
PosixGroup. Their tree looks like this:
dc=example,dc=com
+ ou=ABook
+ ou=groups
+ ou=Infrastructure
+ ou=people
+ ou=posixgroups
+ sambaDomainName=MyDomain


Any idea why they have "groups" and "posixgroups"?


If i would like to add other services than samba, would a directory tree 
like Collax has make more sense than my current "samba-only" tree?

Or should i stick to the smbldap-Tree to be able to use the smbldap 
tools, or can they be easily adjusted?


Thanks, Mario