[Fedora-xen] resizing Xen para-virtualized guest partition

[runmd <runmd comcast net>]

I would like to know if it is possible to resizing Xen para-virtualized guest partition.  For example,

I created a para-virtualized guest as 10GB.  Later down the road I would like to grow it to 20GB.   Can I do this with it being just a file on Dom0.  The only possible solution I can think of is creating a new domU as 20GB and then doing a dd command and copying one virutal disk to another.  But I would like to just grow the guest, if possible.  

Thanks
Terry