Nope, in the end i made new ones. It wasn't hard, but took me a few hours to setup everything like the old ones (or better ^^).
I've found somewhere a thread which states that you can restore them from your snapshots but sadly in my case that wasn't anymore possible.
Another one wrote that you have to create a new plugin-jail with the same name first and replace it by your backed-up jail - i tried that too but that didn't work (maybe i did smth wrong).
I might be possible that my approach, working with cold backups, to restore the jails was wrong, in this case it would be nice to know how to do it right.
