curl -XPUT 'http://127.0.0.1:9200/test/?pretty=1'  -d '
{
   "mappings" : {
      "test" : {
         "_id" : {
            "path" : "foo.bar"
         }
      }
   }
}
'

curl -XPOST 'http://127.0.0.1:9200/test/test?pretty=1'  -d '
{
   "foo" : {
      "bar" : 1,
      "baz" : "xx"
   }
}
'

# [Fri Sep 21 11:14:21 2012] Response:
# {
#    "ok" : true,
#    "_index" : "test",
#    "_id" : "1",
#    "_type" : "test",
#    "_version" : 1
# }

curl -XPOST 'http://127.0.0.1:9200/test/test?pretty=1'  -d '
{
   "foo" : {
      "bar" : [
         2
      ],
      "baz" : "xx"
   }
}
'

# [Fri Sep 21 11:14:23 2012] Response:
# {
#    "ok" : true,
#    "_index" : "test",
#    "_id" : "[",
#    "_type" : "test",
#    "_version" : 1
# }