Did you read the HOWTO-udev_for_dev file that is in the udev
It contains all the info you need to do this.
I've tried similar change before. It didn't work, because the root fs
was read only at that point... but I guess I'll try again with the exact
patch you have, and see what happens.
In the meantime I've switched back to static /dev from devfs, and am
currently being flooded with avc denials, which I shall report to the
selinux list :)