freebsd-update and jails

[Aiza]

If I run freebsd-update on the host updating to 8.0-RELEASE-p3 and then 
run it again with the -b option pointing to the directory tree of the 
jail, I get message saying no update needed to update system to 
8.0-RELEASE-p3. I know the directory tree jail is at 8.0-RELEASE.

If I start a jail and login to its console, I can run freebsd-update 
fetch and it downloads stuff. So it knows the system is not at p3 level. 
But when I run the freebsd-update install, I get error saying all the 
files it wants to touch are read only permission. Just like the jail is 
suppose to do.

Looks like freebsd is inspecting the host to determine what RELEASE it's 
at and NOT the system at the -b option.

Am I doing some thing wrong?

Is this maybe a bug?

Help please.