Groups com.apple.access_afp /calendar/chat...

Question

I have sucessful setup the basic functionality of a 10.5 server.
1 shared folder is availible for guests.
Also I checked, that I can use the iCal and iChat services from a remote workstation.
Now, I added a few users through the workgroup manager.
But non of them can access the server through afp, also iChat and iCal refusing to connect, because of unsucessful authentication.
All users have checked the box: "access account", and, under the open directory options also "allow the user to log in" is checked.
Now, when I compare my admin account to the user accounts, I see, that I am in these additional groups:
com.apple.access_afp
com.apple.access_calendar
com.apple.access_chat
com.apple.access_dns
com.apple.access_mail
com.apple.access_smb
those standard users have not listed these groups.
From the name of the groups, I suspect, that to get access to afp, you have to be a member of com.apple.access_afp.
However, I am unable to assign any of these groups to a user, because those groups are not listed.
I must admit, I am rather new to 10.5 Server,
The last Servers I did setup were 10.0 and 10.2, 10.3
It might be possible I oversee something trivial.

Answer 1

Followup:
Even, If i rechecked in the workgroupmanager that those new users are email-enabled, and have their calender enabled,
If I open the directory manager,
These attributes do not show up.
I looked, if I can restart the directory service, if I can do something else to commit changes/update... But found nothing.
Is it possible, I have to reboot the server after adding a user ? That would be ridiculous.