How to ignore device on fstab on boot?

[vizion communication]

Hi

I have a raid system on a compaq which is arranged as three
disks.

idad1
idad2
idad3

idad3 has one slice /dev/idad3s1 which normally mounts /xyz.

/xyz does not hold any data needed at boot time.

/dev/idad3s1e is in the fstab file but due to missing
superblocks will not mount at boot time - (I inadevertently
trashed it so it lost all copies of the superblock). In
consequence the system does not boot into multi-user to
enable me to newfs /dev/idads1e!

The boot fails with fsck naturally being unable to recover.
What I need to do is persuade the system to boot without
trying to mount /dev/idad3s1e. However when fsck fails in
single user mode I am unable to edit the fstab file and
remove the entry as the file system remains read only.

If I try to newfs from single user /dev/idad3s1e I get
report 'e' partition is unavailable..

If I try and use the disk label editor by booting from the
freebsd 4.7 install disk to newfs from there the label
editor refuses to newfs just that disk because a root
partition has not been defined.

I know there is a simple solution -- I know I have done it
b4 -- but I cannot remember how!!!

David