Access to GPT and partitions within a VND image

[Matthias Petermann <mp%petermann-it.de@localhost>]

Hello all,

I am using file-backed vnds as storage for my Xen domains. In each of 
the vnds there is a GPT with the corresponding partitions.

Is there an easy way to access the GPT and the partitions from outside, 
i.e. preferably from the host to the image file? I would like to 
implement a kind of thin-provisioning, where I copy a base image as a 
sparse file over and over again, and then change a few small things in 
it before the first start of the domain - like the fixed IP address.

Kind regards
Matthias