Modified share permissions not getting to users unless log off done

[Gerry Kirk]

Samba 2.0.6, SuSE 6.1, NT PDC, Win 95/98 clients

Step 1: Create a samba share
Step 2: Access the share from a client machine
Step 3: Modify samba share, e.g., change valid users list
Step 4: Again access share from a client machine

Result: changes in step 3 not recognized from client unless I log off from 
client and re-log in.

Any ideas?

Thanks,
Gerry