[Fedora-xen] How to expand the file created by xenguest-install?

[Denis Forveille]

Does anyone has e detailed procedure to change the size (ie increase) of 
the file that is used as the "xvda" disk by a domU? This is the file 
created by the "xenguest-install" script (or the one created as in 
section 6.2 of the xen user's manual for the file-backed VBDs scenario).

Thanks in advance