How to dynamically bind an existing OpenUI5 Combobox? - sapui5

Question

I'm evaluating OpenUI5 and I'm not clear about the binding concept.
In a XML login view, I have a Combobox that I want to populate after a successful login:
<ComboBox id="cboJoraniInstance" enabled="false" />
So, into my controller I've created an Ajax call with a parameter:
return Controller.extend("sap.ui.jorani.wt.controller.Login", {
onCheckEmail : function () {
var oDialog = this.getView().byId("BusyDialog");
oDialog.open();
var sMail = this.getView().byId("txtEmail").getValue();
var oListInst = this.getView().byId("cboJoraniInstance");
var aData = jQuery.ajax({
type : 'POST',
url : 'http://localhost/dummy/getJoraniInstances.php',
data: {
mail: sMail
},
async: false,
success : function(data,textStatus, jqXHR) {
//Link Combobox
var oModel = new sap.ui.model.json.JSONModel();
oModel.setData(data);
oListInst.setModel(oModel);
oListInst.bindElement("/Instances");
oListInst.bindProperty("value", "Url");
oListInst.bindProperty("name", "name");
oListInst.setEnabled();
},
error: function (jqXHR, textStatus, errorThrown){
MessageToast.show('An error occured');
}
});
oDialog.close();
},
});
The call to my web service is OK and returns:
{
"Instances": [{
"Name": "Local",
"IsDefault": true,
"Url": "http:\/\/localhost\/jorani\/"
}, {
"Name": "D\u00e9mo",
"IsDefault": false,
"Url": "https:\/\/demo.jorani.org\/"
}]
}
The code executes without error, but the control is not filled by my binding attempts.
I've checked the various SO questions on this topic and they all add a new ComboBox into the view dynamically, for example:
oListInst.placeAt("content");
But that is not what I want to achieve, I'd like to fill an existing object. Is it possible?
Concerning the view, if I fill the Combobox with the code below, it is working fine (but it doesn't use the binding feature):
$.each(data.Instances, function(i, obj) {
oListInst.addItem(new sap.ui.core.ListItem({key:obj.Url, text:obj.Name}));
});