How do I make devices usable from a jail?

[Luke]

I'm running CURRENT.  I've set up a jail.  As part of setting it up, I ran 
"mount_devfs devfs /path/to/jail/dev".  This appeared to mount all of my 
devices in the jail at the proper location.
When I start the jail, the jail's /dev looks correct.  It looks 
identitical to the host system's /dev as far as I can tell.  The devices 
are all owned by root, and the permissions on most of them are crw-------.
However, the jail cannot seem to use some of these devices.
For example, when I run sysinstall inside the jail and attempt to install 
packages from the CD, it reports that it does not have permission.  More 
importantly, sshd can't access /dev/random.
crw-r----- 1 root operator  4,  12 Aug 19 09:08 /dev/acd0
crw-rw-rw- 1 root wheel   250,   0 Aug 19 02:08 /dev/random
lrwxr-xr-x 1 root wheel        6   Aug 19 16:40 /dev/urandom -> random
I can't understand why sshd and sysinstall can't use these devices.

The documentation suggests that devfs may have something to do with this, 
but running "devfs rule showsets" from outside the jail yields nothing. 
Running it from inside the jail gives an "operation not permitted" error. 
I suppose I have no "rules".  Is this the problem?  Is the default behavior 
for allowing access to devices from jails more restrictive than when not 
in jails?