Problem installing grub for wubi

[Francesco Stablum]

Hello everyone,

I have been using wubi for three months since now.
Yesterday the windows bootloader got damaged and I thought that it
could have been a nice idea to replace it with grub on the /dev/sda
device.
I used a ubuntu live cd for this purpose.

Actually I managed to install grub with the following commands:

mount -o loop /media/a/ubuntu/disks/root.disk /media/u
grub-install --root-directory=/media/u/ /dev/sda

where /media/a is the mountpoint of the /dev/sda3 partition with windows.

you can read my grub.cfg file at the following page:
http://nopaste.info/10654e8d03.html

The grub.cfg file is located in the ubuntu filesystem image file that
is stored on the windows partition.

Unfortunately at boot grub looks for a device that has the uuid of the
ubuntu filesystem image.
It does not find it and fails to load the grub menu, letting me with a
"grub rescue" prompt.

How can I tell grub-install to configure grub to look into that file
image to search for grub.cfg?

Please let me know if you need other info to solve this problem.

Thank you very much for the attention,
regards,
Francesco Stablum