Grid custom binding to complex model

[rudy]

We have a Kendo grid binding to a custom JSON model.  It looks something like this:

{
    id:  "{GUID}",
    name: "user",
    attributes:
    {
        firstname: "Joe",
        lastname: "Meadows"
     }
}

We are able to get this to bind to the grid using custom templates.  In addition, we are able to allow inline editing to work by configuring
the columnInfo "field" value to be "attributes.fieldname".

However, when we go to save the inline edits, the grid is again confused and is trying to write to the root object.  Example:

{
     id: "{GUID}"
     firstName: "Tony",

    ...
}

How can I get it to properly save my values into my .Attributes collection?

Thank you!