Shrinking a RAID1 device mounted as root?

Hey all...

I'm looking for some help figuring out how to shrink a RAID1 device
that's mounted as root on a Red Hat system.

The device setup is this:
Raiddev	/dev/md0
	Device	/dev/hda1
	Raid-disk	0
	Device	/dev/hdb1
	Raid-disk	1

Hda and hdb are both 36GB ATA hard drives, and each currently has a
partition of about 33GB formatted as Linux RAID autodetect.  Each also
has a swap partition.

What I'd like to do is shrink partition 1 on each disk to around 16GB,
and then create a second RAID1, /dev/md1, with a new partition /dev/hda3
and /dev/hdb3 (leaving the swap device alone.)

I booted off a rescue disk with mdadm, resize2fs, fdisk, etc, and I was
able to shrink /dev/md0 down to 16GB.

I then tried to delete /dev/hda1 and /dev/hdb1 using fdisk, and create 2
new equally-sized partitions in the free space created.  (/dev/hda1,
/dev/hda3, /dev/hdb1, /dev/hdb3, all type Linux RAID Autodetect).
Because /dev/hd[ab]1 is larger than /dev/md0, and the starting block of
the partitions is the same, the filesystem should remain intact.

However, upon rebooting, I ran into a problem.  /dev/md0 cannot be
mounted because of a problem with the superblocks.

I figure that something needs to be done with mdadm to get it to
recognize the "new" /dev/hda1 and /dev/hdb1 as /dev/md0 -- but I don't
want to do a mdadm --create because that will overwrite the filesystem
already on the disks (I think?). 

Is this something that mdadm --assemble can do?  If so, what switches
need to be fed to the command?

Other suggestions?