How to use a sapui5 SmartField without data binding? - sapui5

Question

I can't seem to figure out how to get a SmartField to work without data binding; the problem is that the value that is entered is cleared when there's no data binding.
I've been stuck with this for some days now; I've tried changing the 'sap:' tags in the metadata but to no avail. If I change the field to SmartMultiInput it works fine; there's also a specific example on SAPUI5's tutorial series for SmartMultiInput Without Data Binding - but nothing on SmartField.
myView.view.xml:
<mvc:View
controllerName="sap.ui.demo.smartControls.SmartField"
xmlns="sap.m"
xmlns:form="sap.ui.layout.form"
xmlns:mvc="sap.ui.core.mvc"
xmlns:smartField="sap.ui.comp.smartfield">
<form:SimpleForm
minWidth="1024"
maxContainerCols="2"
editable="true"
layout="ResponsiveGridLayout"
labelSpanL="3"
labelSpanM="3"
emptySpanL="4"
emptySpanM="4"
columnsL="1"
columnsM="1"
class="editableForm">
<form:content>
<smartField:SmartLabel labelFor="idProduct"/>
<smartField:SmartField value="{ProductId}" entitySet="Products" id="idProduct"/>
</form:content>
</form:SimpleForm>
</mvc:View>
myController.controller.js
sap.ui.define([
"sap/ui/core/mvc/Controller"
], function(Controller) {
"use strict";
return Controller.extend("sap.ui.demo.smartControls.SmartField", {
onInit: function() {
//SmartField will work if the following code is uncommented
//this.getView().bindElement("/Products('4711')");
}
});
});
metadata.xml
<?xml version="1.0" encoding="utf-8"?>
<edmx:Edmx Version="1.0"
xmlns:edmx="http://schemas.microsoft.com/ado/2007/06/edmx"
xmlns:m="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata"
xmlns:sap="http://www.sap.com/Protocols/SAPData">
<edmx:DataServices m:DataServiceVersion="2.0">
<Schema Namespace="com.sap.wt02"
sap:schema-version="1" xmlns="http://schemas.microsoft.com/ado/2008/09/edm">
<EntityType Name="Product">
<Key>
<PropertyRef Name="ProductId" />
</Key>
<Property Name="ProductId" Type="Edm.String" />
<Property Name="Price" Type="Edm.String"
sap:unit="CurrencyCode" MaxLength="3" sap:label="Price"
sap:updatable="true" />
<Property Name="CurrencyCode" Type="Edm.String"
MaxLength="3" sap:label="Currency" sap:semantics="currency-code"
sap:updatable="true" />
</EntityType>
<EntityContainer m:IsDefaultEntityContainer="true"
sap:supported-formats="atom json">
<EntitySet Name="Products" EntityType="com.sap.wt02.Product" sap:creatable="true" sap:updatable="true" sap:addressable="true" sap:deletable="true" />
</EntityContainer>
</Schema>
</edmx:DataServices>
</edmx:Edmx>
Products.json
[
{
"ProductId": "4711",
"Price": 856.49,
"CurrencyCode": "EUR"
}
]