Mounting LVM root disk from rescue disk boot

[Dave Atkinson]

Hi Fedora world,

Can anyone help with this?  I have tried a little googling, with no
success...

Having just installed FC3 x86_64 on my new Athlon 64 box, I decided it
would be nice to have i386 installed to deal with a few of the 'issues'
I've encountered.  So I need to shrink the root partition, which I let
the install routine create on an LVM partition spanning all available
space on the hard disk (there is only one).  So, I know how to use LVM
and e2fs tools to resize the partition, but I obviously need to have the
partition unmounted.  Now, when the system is booted normally, it tells
me that the root partition is /dev/mapper/VolGroup00-LogVol00.  If I
boot the Rescue CD and skip mounting my root partition (in order to
resize it) and I type

resize2fs /dev/mapper/VolGroup00-LogVol00 40000

I get something like "file not found" which I presume relates to the
above device file, which indeed does not exist.  I tried 

resize2fs /dev/VolGroup00/LogVol00 and got a similar error.

Can anyone shed some light on this?  The only articles I've found on
't'net deal with volumes other than one's root partition...

Thanx in advance,
Dave A.