Centos Xen resizing DomU partition and volume group

I have a setup like so:

      Dom0 LV
         |
 DomU Physical Disk
    |           |

  XVDA1       XVDA2
 (/boot)    (DomU PV)
                |
            VolGroup00
            (DomU VG)
            |        |
      LogVol00       LogVol01
       (swap)         (/)

I am trying to resize the DomU root Filesystem. (VolGroup00-LogVol01) I realize that I now need to resize the partition XVDA2, however when I try doing this with parted on Dom0 it just tells me "Error: Could not detect file system."

So to resize the root part VolGroup-LogVol00 shouldn't the process be:

# Shut down DomU
xm shutdown domU

#Resize Dom0 Logical volume
lvextend -L+2G /dev/volumes/domU-vol


# Parted 
parted /dev/volumes/domU-vol

# Resize root partition
resize 2 START END

(This is where I get an error) "Error: Could not detect file system."


# add the vm volume group to Dom0 lvm

kpartx -a /dev/volumes/domU-vol

# resize the domU PV
pvresize /dev/mapper/domU-pl (as listed in pvdisplay)

# The domU volume group should automatically adjust
# resize the DomU lv
lvextend -L+2G /dev/VolGroup/LogVol00

And then obviously increase the fs, remove the device from kpartx etc

The problem is I dont know how to resize the partition? How do I resize this partition so I can run pvresize on the DomU?

Thanks