No, you cannot use Web Client server or vCenter as your own database or storage server. Since you are using custom objects you must provide your own back-end process/database where that data resides. The java plugin you are adding to access get that data in the Virgo middle tier is just a "pass-through", i.e. your data adapter must be capable of fetching your custom data from your own back-end (using whatever API or communication protocol is most suited for you)
The main reason the current Chassis sample code uses an in-memory object store is to simplify the SDK setup. As the header say in ObjectStore.java this is not the correct way to handle data in a production application.
