Open an SR
Only a guess. See whether you can use "Recompose" on the pool to select the renamed VM and its snapshot, rather than trying to edit the pool settings.
What happens when you click the Browse button for the Snapshot first, i.e. before the one for the Parent VM?
If you are moving your master image from vcenter, you should first consider recomposing/push operation on pool to reselect the correct parent VM and snapshot path before editing the pool. Obviously it will not show the image path since it is not located in actual location.
My point is the Flash/Flex console allows me to select the renamed image when editing the pool, but the HTML console does not. That is not feature parity in my opinion, and the HTML console should be able to handle this. (There are other things that are missing from HTML but I haven't started a thread about it yet)