Nested Objects Sorting

According to ES documentation: http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/search-request-sort.html

That is possible to sort documents by "nested objects".

Does ES instance provided by episerver find supports this?

Or I doing something wrong below?

Mapping that was build in my index (extracted from it):

{"Commerce_Business_Search_ProductDocument": {"dynamic_templates": [
      {"nested_template": {"mapping": {"type": "nested"
          },"match": "*$$nested"
        }
      }
    ],"properties": {"Prices$$nested": {"type": "nested","properties": {"UnitPrice$$number": {"type": "double","ignore_malformed": false
          }
        }
      }
    }
  }
}

Query:

{"sort": [{"UnitPrice$$number": {"nested_path": "Prices$$nested","mode": "min","order": "desc","ignore_unmapped": false
        }
    }],"fields": ["___types", "Prices$$nested"]
}

Hits from index (I have only 2 documents there)

[
    {"_index": "yauheni_myindex","_type": "Commerce_Business_Search_ProductDocument","_id": "247","_score": null,"fields": {"Prices$$nested": [
            {"___types": ["Commerce.Business.Search.ProductPrice","System.Object"
                ],"ValidFrom$$date": "2014-03-19T12:11:00Z","Warehouse$$string": "","UnitPrice$$number": 10,"$type": "Commerce.Business.Search.ProductPrice, Commerce.Business","Market$$string": "Sweden","ValidUntil$$date": "2015-03-19T12:11:00Z"
            }
            ],"___types": ["Commerce.Business.Search.ProductDocument","System.Object"
            ],"sort": [
              0
            ]
        }
    },
    {"_index": "yauheni_myindex","_type": "Commerce_Business_Search_ProductDocument","_id": "248","_score": null,"fields": {"CatalogEntryId$$number": 248,"Prices$$nested": [
            {"___types": ["Commerce.Business.Search.ProductPrice","System.Object"
                ],"ValidFrom$$date": "2014-03-19T12:11:00Z","Warehouse$$string": "","UnitPrice$$number": 20,"$type": "Commerce.Business.Search.ProductPrice, Commerce.Business","Market$$string": "Sweden","ValidUntil$$date": "2015-03-19T12:11:00Z"
            }
            ],"___types": ["Commerce.Business.Search.ProductDocument","System.Object"
            ],"sort": [
              0
            ]
        }
    }
]

Hits are not sorted, and "sort" fields equals 0 for both of them.