http://www.freebsd.org/doc/ru/books/handbook/kernelconfig-devices.html

# dmesg

# ls -l /dev/cuaa0

[hostX:~] # cd /etc
[hostX:/etc] # mkdir devd
[hostX:/etc] # cd devd

[hostX:/etc/devd] # cat my.conf 
attach 30 {
        device-name "umass0";
        action "sleep 3; /sbin/mount -t msdos /dev/da0s1 /mnt/";
};