default file permissions

[Linda]

I have a user that I would like to set up so his files have 
different default file permissions than the system.  I have 
done this in the past when users were working inside 
terminal windows by setting umask in .bashrc However this 
user only is on the system to use email and a web browser. 
He is saving a file to an auto mounted nfs  that mounts in 
his home direct from thunderbird . I have tried setting 
umask in .bashrc and in .xsessionsrc but neither seem to 
effect the file permissions.   Any ideas how I can get this 
to work?  Otherwise is there a way to have the permissions 
for all files created in a specific directory to have a set 
default permission, with the cavaet that this is really a 
nfs directory mounted on his machine not really a local file 
directory.
                          Thanks
                           Linda