samba - Mar 2005 - srvtools : only able to assign primary group

Hello to all. I'm testing Samba as a domain controller (I'm using 
tdbsam). All is working perfectly so far, but I have an issue when using 
srvtools to manage my users. I'm only able to assign the primary group 
to an user account. All additionnal groups added to the "member of:" 
section are ignored (I press OK and the srvtools don't complain or 
anything, but when I come back to see groups assignment they are all 
gone to the exception of the group that I have set as the primary group).
The only way that I have find to make an user member of more than one 
group is to create additional group maps directly on the server with the 
command net groupmap. For example :

- With srvtools I set the primary group for the user "Joe" to the
group
"Sales department" (if I try to add any others groups they are simply 
ignored)
- On the server I execute the following command : net groupmap add 
ntgroup="User joe" unixgroup=joe
- Now I go back to srvtools and I can effectively see the two assigned 
groups in the "member of:" section

However, at this point a new problem arise with srvtools. If srvtools 
see than an user is member of more than one group, then I'm no longer to 
remove group(s) for this user (srvtools popup an "Access is denied" 
error message when I'm validating the group removal).
Is that a known issue? Is me better to dump the use of srvtools (I have 
to admit that I like to use srvtools to manage my users and groups).

PS - srvtools work perfectly to add and remove users and groups (I only 
have a problem with the issue mentionned). I'm using Fedora Core 3 and 
samba-3.0.10-1 (installed via yum). Thanks for any help.