It's rather dangerous to just use the mknod command directly like that.

There is a devlinks utility that will recreate the symbolic links in the /dev directory. There is also a drvconfig utility that can create the stuff in the /devices utility.

Sun has a notion of a "reconfiguation" reboot and I think that this is the safest approach for a start. You just "touch /reconfigure" and then you reboot. The start-up scripts notice the file /reconfigure and run stuff like drvconfig and devlinks automatically.