Sorry again, i've just messed up the whole matter. To put it simply: umountfs and umountroot don't unmount filesystems at shutdown/reboot (therefore resulting in a filesystem recovering at each boot - so if i want to avoid recovering i have to switch to runlevel 1 and unmount filesystems read-only before shutdown/reboot every time [all done via sysrq] -): i've setted these services in runlevels 2,3,4,5 without success (no unmounting at all); then i've tried runlevels 0,6 and still nothing. I've also tries runlevel S and again all runlevels (both services setted on 1,2,3,4,5,0,6 and S). Still nothing.

Hello again, i've setted 0 and 6 on "Default-Stop" but i still doesn't unmount the filesystems:
                               
#! /bin/sh
### BEGIN INIT INFO
# Provides:          umountfs
# Required-Start:
# Required-Stop:     umountroot
# Default-Start:        0 6
# Default-Stop:
# Short-Description: Turn off swap and unmount all local file systems.
# Description:
### END INIT INFO

#! /bin/sh
### BEGIN INIT INFO
# Provides:          umountroot
# Required-Start:
# Required-Stop:
# Should-Stop:       halt reboot kexec
# Default-Start:      0 6
# Default-Stop:
# Short-Description: Mount the root and /usr filesystems read-only.
### END INIT INFO

#! /bin/sh
### BEGIN INIT INFO
# Provides:          umountnfs
# Required-Start:
# Required-Stop:     umountfs
# Should-Stop:       $network $portmap nfs-common
# Default-Start:      0 6
# Default-Stop:
# Short-Description: Unmount all network filesystems except the root fs.
# Description:       Also unmounts all virtual filesystems (proc,
#                    devpts, usbfs, sysfs) that are not mounted at the
#                    top level.
### END INIT INFO