[Migration 1.5] Howto mount my css package resource?

[Mike Mander]

Hi,

i couldn't find a working solution until now for the following usecase.
I would like to include a css file from my package structure in a page.
It sits in <package-path>/res/css.

I included the css in my page:

<code>
    @Override
    public void renderHead(IHeaderResponse response) {
        super.renderHead(response);
        response.renderCSSReference(CssHolder.SCREEN);
    }
</code>

The css holder is a holder for my resourcereferences
<code>
public class CssHolder {
    public static final ResourceReference SCREEN = new 
SharedResourceReference("shop/screen.css");
    public static final ResourceReference PRINT = new 
SharedResourceReference("shop/print.css");
}
</code>

I mounted the resource in application.init():
<code>
        mountResource("shop/screen.css", new 
PackageResourceReference(getClass(), "res/css/screen.css"));
        mountResource("shop/print.css", new 
PackageResourceReference(getClass(), "res/css/print.css"));
</code>

But it is not referenced correctly. In html-output it is

<link  
rel="stylesheet"type="text/css"href="wicket/resource/org.apache.wicket.Application/shop/screen.css
  <view-source:http://localhost:8080/wicket/resource/org.apache.wicket.Application/shop/screen.css>"/>

In my logs i can find some messages like these, but i don't have a glue what i 
have to do now.
WARN  - ResourceReferenceRegistry  - Asked to auto-create a ResourceReference, 
but ResourceReferenceRegistry.createDefaultResourceReference() return null.  
[scope: org.apache.wicket.Application; name: shop/screen.css; locale: null; 
style: null; variation: null]

Can someone please point me the direction?
Thanks
Mike