multi-boot+grub2+separate boot partition

["Russell L. Harris" <rlharris@broadcaster.org>]

I wish to use grub2 to multi-boot the following systems:

    => Debian "stable" (Squeeze) on /dev/sda6

    => Debian "testing" (Wheezy) on /dev/sda7

    => Ubuntu (10.x)             on /dev/sda8

This is a "work" machine and my primary interest is "stable".  But I
need to become familiar with Wheezy, which is about to become
"stable".  I am installing Ubuntu as a safety net, because Ubuntu
developers seem to find a way to get all of the peripheral devices
working, even if it the resulting configuration is non-standard.

I have read the Debian installation manual and I have searched with
Google, but thus far I have not found a HOWTO for such an arrangement
using a separate boot partition.

I plan to update "testing" from time to time.  Once Wheezy becomes
"stable", I plan to drop Squeeze and install the new "testing".  I may
even update Ubuntu.

It seemed to me that the proper approach would be to use a separate
boot partition on /dev/sda1, and to make it policy always to run
"update-grub" from "stable".

I instructed the Squeeze installer to install grub2 to /dev/sda1.
I instructed the Wheezy  installer to install grub2 to /dev/sda7.
I instructed the Ubuntu  installer to install grub2 to /dev/sda8.

I booted into Squeeze and executed "update-grub".  The messages were:

    => found linux-image /boot/vmlnuz-2.6.32-5-686 (this is Squeeze)

    => found linux-image /boot/initrd-2.6.32-5-686 (this is Squeeze)

    => found Debian GNU/Linux (Wheezy/Sid) on /dev/sda7

    => Ubuntu 10.10 on /dev/sda8

But upon rebooting, the grub menu contains only entries for Squeeze
and Ubuntu.

Is it reasonable to use a separate boot partition?  Can this scheme be
made to work?

RLH