Items File - Additional parameters

I’m wondering if there it is possible to add stateDescription and category via the *.items file? Using the REST API, I see some additional parameters in items that are created automatically, but I am not able to duplicate these in my manually created items file. Below is what I’m trying to create:

{
  "link": "http://192.168.1.12:8080/rest/items/VSX1021_VolumeDimmer_zone1",
  "state": "-19.82702702702702168835457996465265750885009765625",
  "stateDescription": {
    "minimum": -80,
    "maximum": 12,
    "step": 0.5,
    "pattern": "%.1f dB",
    "readOnly": false,
    "options": []
  },
  "type": "Number",
  "name": "VSX1021_VolumeDimmer_zone1",
  "label": "Volume",
  "category": "SoundVolume",
  "tags": [],
  "groupNames": []
}

As of now the only things that can be defined in an .items file is what is described in the docs.

http://docs.openhab.org/configuration/items.html