I am very new to Gson and probably the answer to my problem is very simple.I have a WCF service that return a custom object serialized in Json by JSON.NET like this:
{"$id":"1","ID":261,"Email":"custome...@gmail.com","DeviceID":"08ebee0b-cfcd-4fb4-9d74-b6571a672134","Country":"Italia","IntallationData":"2012-07-16T08:41:53"}