Problem adding CSS resources in Wicket 6

I have a problem adding CSS resources to Wicket pages in Wicket 6.

In my page class, I override renderHead() like this:

@Override
public void renderHead(IHeaderResponse response) {
response.render( CssHeaderItem.forReference( new CssResourceReference(
MyFantasticPage.class, "MyFantasticPage.css" ) ) );

However, in the resulting HTML code, the link to the CSS file is rendered by
Wicket like this:

<link rel="stylesheet" type="text/css"
href="./wicket/resource/com.myDomain.pages.MyFantasticPage/MyFantasticPage-ver-1406325551266.css"
/>

The link is correct except for this portion: "-ver-1406325551266"

How can I prevent Wicket from adding this extra noise? This is happening in
my entire application for every single page. I've tried a few variations on
my renderHead() implementation, but no luck.

Thank you very much!