JBC is a p2p based cache, and there is no client-server module as such (at least not at the moment).
However, there is something you can do: use the TcpDelegatingCacheLoader. Set up cache instances on each VM, as a "light" front-cache, with an aggressive eviction policy so it doesn't impact memory usage on the client VMs much, and these should also be configured with a TcpDelegatingCacheLoader that points to a central, dedicated cache instance fronted by a TcpCacheServer.
Provided, of course, that is what you are trying to achieve. :)
Oops. This is nice. Spares me from having to set up my own JTA transactions (to span both JMS and JBC) and I get improved performance through local caching as well ;-). I'm thinking of adding a Linda-style frontend to JBC similar to JavaSpaces. Will be a spare time effort. So I will have to see how far I get within reasonable time. But I guess it will be fun.