How can I normalize my errors for the RESTAdapter?

My errors come back like this:

{
    "error": {
        "code": 422,
        "message": "Malformed data",
        "errors": {
            "to_user": [
                "Invalid receiving user"
            ]
        }
    }
}

Where ember expects:

{
    "errors": {
        "to_user": [
            "Invalid receiving user"
        ]
    }
}

How can I normalize my data and make the errors bind properly?