How can I set content pane widgetid attribute when?

```
new dijit.layout.ContentPane({
    content: "<p>Optionally set new content now</p>",
    style: "height:125px",
    // I can set id, but widgetid will differ
    id: 'someId',
    // no effect
    widgetid: 'myWidgetId',
    // still fail
    widgetId: 'how can I set you, God damn it?!'
}

```

I need it for content pane finding with dijit.byId(), as this method gets the element by it's widgetid attribute.