[go-nuts] mongo and go

Hi,
I try to learn go and for my experience to port nodejs little project to go.
I must insert/update data into my mongodb, simple document structure works
well.
But I have a more sophistical document structure like this :

{
   "_id": "20130526-6000-19",
   "answere_wait_time": NumberInt(0),
   "call_daily": NumberInt(5),
   "call_hourly": {
     "1": NumberInt(5)
   },
   "call_minute": {
     "1": {
       "34": NumberInt(1),
       "41": NumberInt(2),
       "42": NumberInt(1),
       "44": NumberInt(1)
     }
   }
   },
   "metadata": {
     "user": "6000",
     "dt": ISODate("2013-05-26T03:00:00.0Z"),
     "disposition": NumberInt(19)
   }
}

What is right/smart way to represent my upsert in golang ?
Thank for help