CAUTION: with the following the system is up so you risk file loss, data loss, etc. — use at your own risk.
Ideally you would shutdown your domU and use vm-export rather than vm-snapshot.
make a snapshot
xe vm-snapshot vm=name new-name-label=name-foo
this returns a uuid
xe vm-export vm=UUID filename=|bzip2 > file.xva.bz2
move the file about
scp 192.168.1.2:file.xva.bz2 file.xva.bz2
import the snapshot
cat file.xva.bz2 |ssh 192.168.1.1 "bunzip2|/opt/xensource/bin/xe vm-import filename=/dev/stdin"
then recreate the clone from the snapshot template under openxenmanager or other management tool.