Problems probing a LVM device with GRUB2

[Alberto Luaces <aluaces@udc.es>]

Hello,

I'm trying to install GRUB2 to a disk that has an ext2/3 filesystem into
a LVM partition. I can even start the system from GRUB2 and a boot disk,
so it should work.

The problem is that `grub-install' displays `no such disk' errors. I
have tracked it down to `grub-probe':

$ ls /dev/mapper/
control  lvm_volume-debian_root  lvm_volume-swap

$ sudo grub-probe -d /dev/mapper/lvm_volume-debian_root 
grub-probe: error: no such disk.

How can I make `grub-probe' to find the partition? I'm using Squeeze,
with latest GRUB2:

$ dpkg -l grub-pc
[...]
ii  grub-pc                                        1.98+20100804-4  

Thanks,

-- 
Alberto