[Samba] Windows XP - Userid in the Start Menu

[Renato Loffreda]

I am running smbldap-tools-0.9.1-1 and samba-3.0.23c-2.el5.2.0.2 on 
Centos 5 as a PDC.

This is a problem that I have had for now 3 years on my first PDC
running on RH AS4.

Here is the problem.

I login from my workstations running Win XP, I then click on the Start
Button (bottom Left).  The very top of the popup window displays the
fullname of the user (i.e. first, initial and lastname).

After some time, the fullname gets replaced my the userid.

How do I stop this from happening?

Thanks

Renato