Installing Debian Jessie/testing via debootstrap

[dgiglio@iol.it (daniele.g)]

Hi

I've installed debian testing from within stable using debootstrap
(following https://www.debian.org/releases/stable/i386/apds03.html). At
the moment this is my partition table:

--8<---------------cut here---------------start------------->8---
    NAME                           MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
    sda                              8:0    0 111,8G  0 disk
    ├─sda1                           8:1    0   243M  0 part /boot
    ├─sda2                           8:2    0     1K  0 part
    └─sda5                           8:5    0 111,6G  0 part
      ├─nostromo-CRUNCHBANG (dm-0) 254:0    0    14G  0 lvm  /
      ├─nostromo-swap_1 (dm-1)     254:1    0   4,1G  0 lvm  [SWAP]
      ├─nostromo-DEBIAN (dm-2)     254:2    0    14G  0 lvm  /media/DEBIAN
      ├─nostromo-LOCAL (dm-3)      254:3    0   9,3G  0 lvm  /usr/local
      └─nostromo-HOME (dm-4)       254:4    0  70,2G  0 lvm  /home
--8<---------------cut here---------------end--------------->8---

The boot partition only contains the stable kernel, while the DEBIAN
partition contains its own kernel. I did *not* install any boot loader
in it, since I'd want avail of the already existing boootloader. 
What's the proper way to add the testing entry to the GRUB menu? Running
"update-grub" in the host distro does not work. 

Any clue?
Thanks in advance.