Created Issue: Content-negotiation not done properly for odata actions using json [766]

When calling an action in odata, content negotiation it's not being performed properly.

POST http://localhost:26000/EntityWithSimpleProperties(1)/TestAction HTTP/1.1

Host: localhost:26000
Content-Length: 46
Content-type: application/json
Accept: application/atom+xml

{
"entity": true,
"clave": "password"
}

HTTP/1.1 200 OK
Cache-Control: no-cache
Pragma: no-cache
Content-Type: application/json; charset=utf-8
Expires: -1
Server: Microsoft-IIS/8.0
DataServiceVersion: 3.0
X-AspNet-Version: 4.0.30319
X-SourceFiles: =?UTF-8?B?Qzpcd29ya1xPRGF0YUNvbXBhcmlzb25TZXJ2aWNlXE9EYXRhQ29tcGFyaXNvblNlcnZpY2UuV2ViQVBJXEVudGl0eVdpdGhTaW1wbGVQcm9wZXJ0aWVzKDEpXFRlc3RBY3Rpb24=?=
X-Powered-By: ASP.NET
Date: Fri, 11 Jan 2013 23:46:07 GMT
Content-Length: 136

{
"odata.metadata":"http://localhost:26000/$metadata#Collection(Edm.String)","value":[
"Hello","World","OData","Actions"
]
}