diff -Nuarp src/samba4-4.0.0~beta4/source4/scripting/python/samba/join.py samba4-4.0.0~beta4/source4/scripting/python/samba/join.py
--- src/samba4-4.0.0~beta4/source4/scripting/python/samba/join.py	2011-12-13 19:42:56.000000000 +0100
+++ samba4-4.0.0~beta4/source4/scripting/python/samba/join.py	2011-12-23 03:51:11.000000000 +0100
@@ -141,6 +141,14 @@ class dc_join(object):
         ctx.managedby = None
         ctx.subdomain = False
 
+        ctx.next_rid = None
+        if ctx.keep_existing:
+            res = ctx.samdb.search(base=ctx.promote_from_dn,
+                                   expression='(&(CN=RID Set)(rIDNextRID=*))',
+                                   attrs=["rIDNextRID"])
+	    if res:
+                ctx.next_rid = res[0]["rIDNextRID"][0]
+
     def del_noerror(ctx, dn, recursive=False):
         if recursive:
             try:
@@ -648,6 +656,7 @@ class dc_join(object):
                 schemadn=ctx.schema_dn, configdn=ctx.config_dn,
                 serverdn=ctx.server_dn, domain=ctx.domain_name,
                 hostname=ctx.myname, domainsid=ctx.domsid,
+                next_rid=ctx.next_rid,
                 machinepass=ctx.acct_pass, serverrole="domain controller",
                 sitename=ctx.site, lp=ctx.lp, ntdsguid=ctx.ntds_guid,
                 use_ntvfs=ctx.use_ntvfs, dns_backend=ctx.dns_backend)