devfs: how do I stop permissions being reset at reboot?

[R Kimber]

I'm trying to run nut with a newly acquired UPS using COM1.  This
involves doing

chmod 0600 /dev/ttyS1
chown nut.nut /dev/ttyS1

However, these permissions are reset at reboot to

crw-rw----  1 root dialout 4, 64 2006-03-12 18:02 /dev/ttyS0

How should I make my own changes permanent?

Thanks.
-- 
Richard Kimber
http://www.psr.keele.ac.uk/