I see. Isn't this a bit odd? Open-E surely uses LVM and LVM does provide the ability to move data from PVs to other extents to be able to remove PVs from the VGs.
Otherwise its like it is now: now, I will have to remove my VG00 altogehter. This is not a real problem for now, since this is my replication target, but I do find this a bit cumbersome. Especially if this happens to you when you have bigger volumes and thus enormous backup/restore times.