10.04 shutdown dont flush disks

Installed Ubuntu 10.04 desktop on Acer Aspire 5542, 64 bits.
Whenever I shutdown (or restart) the machine, both from the GUI menu or from command line, the disks are not flushed, so every time the system runs fsck and find errors.

But if I shutdown or restart using the "magic keys" ( found it one hour ago... ) Ctl-Alt-SysReq R S E I U O, all is fine.

Seeing /etc/rc0.d contents, I find

K01kerneloops K20noip2 S01halt S02urandom
K01laptop-mode K20openbsd-inetd S01sendsigs S02wpa-ifupdown
K02bluetooth K20vboxdrv S01umountfs S35networking
K04vmware K21postgresql-8.4 S01umountnfs.sh
K20exim4 K31atieventsd S01umountroot
K20hddtemp README S01unattended-upgrades

IMO the strange thing here is that "halt" runs in the same order as umount* ( S01 ), so it's feasible that the machine stops before disk flushing.

How could I change this to a more robust arrangement?

TIA

PS: it's so uncomfortable to maintain those 3 keys stuck together ...