fsck on reboot in 5.x

Hi,

The other day I had the first power failure on a RELENG_5_1 machine, and
much to my surprise, it didn't resume normal operation because of fsck
issues (long lines):

[joan_at_iaeste-catalunya:~]0 $grep fsck /tmp/dmesg 
WARNING: R/W mount of / denied.  Filesystem is not clean - run fsck
WARNING: R/W mount of / denied.  Filesystem is not clean - run fsck
WARNING: R/W mount of /fs/tmp/mount denied.  Filesystem is not clean - run fsck
WARNING: R/W mount of /fs/home/mount denied.  Filesystem is not clean - run fsck
WARNING: R/W mount of /fs/std-var/mount denied.  Filesystem is not clean - run fsck
WARNING: R/W mount of /fs/aegee/mount denied.  Filesystem is not clean - run fsck

Apparently, FreeBSD didn't even bother actually fsck'ing, not even in
the background. The problem is the without a rw /var I can't login
remotely :( I've set fsck_y_enable=yes now in rc.conf but am afraid it's
not what I need. Desired behaviour would be to mount all the fs's ro
until the background fsck is completed, moment at which the should be
remounted rw. I've read through rc, rc.subr and rc.conf but have not
figured out how to accomplish this :(

So, can anyone enlight me about how to make FreeBSD postpone rw mount of
dirty fs's until bgfsck has finished?

tks
--
pica