I configured a geoserver store with an external WMS. I used the following WMS url
Once I saved the store, Geoserver listed the layers on the screen. I clicked the "Publish" link of the "DEMO" layer and I saved it with the default options.
When I display the layer preview, the layer has a wrong projection and is repeated many times. Here you can see the image: http://stackoverflow.com/questions/14336018/geoserver-cascading-wms-wrong-projection
The projection of the layer seems to be wrong. I tried to force to another projection or to keep the native one but results are not better.
Have you any ideas about the problem?