Save nested form data back to server in ExtJS

I have a model that contains an association with another model. I can display nested data in a form using the display attribute on the field. Example:

Ext.define('Example.model.Request', {
    extend: 'Ext.data.Model',

    fields: [
        {
            name: 'id',
            type: Ext.data.Types.NUMBER,
            useNull: false
        }
        {
            name: 'plan_surveyor',
            mapping: 'plan.surveyor',
            type: Ext.data.Types.STRING
        }
    ],

    associations: [
               {type: 'hasOne', associationKey: 'plan', getterName:'getPlan', model: 'Specs.model.Plan'}
              ],

    proxy: {
            type: 'direct',
            api: {
                read: requestController.load,
                 update: requestController.update,
            },
            reader: {
                type: 'json',
                root: 'records'
            },
            writer: {
                type: 'json',
                writeAllFields: true,
                nameProperty: 'mapping'
            }
        }

    });

      

        
        
        
      

    

Using this method, I can display the plan.surveyor value in the form under the plan_surveyor link. I am calling Form.loadRecord (model) to pull data from the model into the form.

However, now when I try to send data to the server, I get the error:

Error performing action. Please report the following: "Unrecognized field "plan.surveyor"

I am trying to save to the server by first calling Form.updateRecord (model) then model.save (). Is there a way for Writer to understand that "plan.surveyor" is not a property name and instead handles nesting correctly?

Am I doing this right to get started, or do I just need to handle the form data settings and load back into the model more manually? It looks like nested data isn't all that well supported in general - any recommendation?