How to search tweets based on date and time?


When I use the REST API v1.1 search endpoint to search tweets using the until since parameters, I get systematically no result.
It looks like that these parameters are not parsed correctly.
For exemple if I make this search query :
I get this result :

  "statuses": [],
  "search_metadata": {
    "completed_in": 0.007,
    "max_id": 0,
    "max_id_str": "0",
    "query": "gamer+until%3A2013-01-01",
    "count": 15,
    "since_id": 0,
    "since_id_str": "0"

Is there any encoding or parameter misuse problem that I am missing here?