mount a partition on a dir in the home of a user

["aldo maggi" <aldo.maggi@gmail.com>]

i use debian sid
recently i resized /dev/hda1 (winxp preinstalled in the notebook) in
order to have more space available for my documents (my debian is on
/dev/hda4)
the new partition, /dev/hda5, should be mounted on
/home/myuser/documents, a dir which has permissions 770 and owner
myuser.myuser
i wrote a new record in /etc/fstab:
/dev/hda5  /home/myuser/documents  ext3  defaults,user  0   0
the problem is that any time i reboot, permission and ownership on
/home/myuser/documents are changed: root.root and 755, if i umount (as
root) the partition the previous settings are restored
(/home/myuser/documents 770 myuser.myuser)
i read carefully man mount but could not find a solution, i changed
several times the record relevant to /dev/hda5, now i have:
/dev/hda5  /home/myuser/documents ext3
defaults,user,exec,dev,suid,grpid
but cannot get ownership myuser.myuser, permissions 770.
what should be the solution to this problem? (well, one could be lvm
.... but i'd like to avoid messing around with a kernel which is
already heavily patched)
thanks
aldo