The N800 does ignore fstab. I opened a bug a while ago on this, and was told that fstab was not flexible enough, so they have a script (osso-mmc-mount.sh) that runs when it detects the card is available.

I suppose you could hack the script to mount your card somewhere else. Or you could take a path of lesser resistance, and just simbolically link your /Root to /media/mmc2.

Hope this helps,

Craig...