Boot DoudouLinux with loopback grub function

[Amicale Salmson]

Hello all,

I want to boot DoudouLinux ISO file from my hard disk.
http://www.doudoulinux.org/

I use the following grub configuration :
/etc/grub.d/40_custom:
Code:
menuentry "Doudou Linux" {
  loopback  loop (hd0,msdos1)/boot/doudoulinux-2010-11-fr.iso
  search --set -f /boot/doudoulinux-2010-11-fr.iso
  linux     (loop)/live/vmlinuz 
findiso=/boot/doudoulinux-2010-11-fr.iso toram=filesystem.squashfs 
boot=live noeject
  initrd    (loop)/live/initrd.img
}

The kernel works fine, but not the filesystem.
At the end of the kernel loading, I have the following messages several 
times :
- kjournald starting commit interval 5 seconds
- ext3-fs: mounted filesystem with ordered data mode

Then busybox tell me :
"unable to find a medium containing a live filesystem"

The DoudouLinux ISO contains :
├── isolinux
│   ├── boot.cat
│   ├── exithelp.cfg
│   ├── f1.txt
│   ├── f2.txt
│   ├── f3.txt
│   ├── f4.txt
│   ├── f5.txt
│   ├── isolinux.bin
│   ├── isolinux.cfg
│   ├── live.cfg
│   ├── menu.cfg
│   ├── prompt.cfg
│   ├── splash.png
│   ├── stdmenu.cfg
│   └── vesamenu.c32
├── live
│   ├── filesystem.squashfs
│   ├── initrd.img
│   ├── packages.txt
│   ├── parameters.txt
│   └── vmlinuz
└── md5sum.txt

Can anyone help me?

Regards,
jm.