samba - Dec 2009 - LDAP_NO_SUCH_OBJECT upon new user creation in s4/OpenLDAP

Hi all,

for some weeks now I am trying to set up Samba4 (alpha9) with an 
OpenLDAP 2.4.17 backend as an AD PDC for my XP/7 clients. It was working 
for some time with Samba's integrated LDAP facility, however I could not 
figure out how to use this database e.g. to authenticate my IMAP users 
against (bind-dn, port etc.).
OpenLDAP was compiled from source using --enable-modules=yes and 
--enable-overlays=yes. Provisioning samba using the command line

setup/provision --ldap-backend-type=openldap 
--slapd-path="/usr/sbin/slapd" --username=samba-admin 
--realm=localdomain --domain=Heimnetz --server-role='domain controller' 
--adminpass=somepass

ran through, although there were errors about slapd (id2entry.bdb not 
found, NT_STATUS_UNEXPECTED_NETWORK_ERROR, slapd unable to start). 
Afterwards, slapd and samba start fine, I can join machines to the 
domain "Heimnetz" (DNS is also working properly), login using the 
"administrator" account and have a look at the AD via dsa.msc.
Was is NOT working is the creation of new users. Doing that in dsa.msc 
failes with an error message about password policies, but this is 
probably not yet implemented, right?
Going the howto-way, "<source-dir>/setup/newuser blah" prompts
for a
password, displays messages about skipping the loading of schema, naming 
context details and domain details, and then failes with the following 
error message:

_ldb.LdbError: (32, 'objectclass: Cannot add 
CN=blah,CN=Users,DC=localdomain, parent does not exist!')

Parsing the logs of slapd I see that "newuser" performs several
searches
in the directory that slapd all answers with err=32 
(LDAP_NO_SUCH_OBJECT), although in phpLDAPadmin I can see that the 
requested objects exist, including CN=Users,DC=localdomain with 19 
entries after a fresh provisioning.

Any help would be greatly appreciated.
Regards, Eric