title: Geoserver WMS layer does not show up in OpenLayers
body: <p>I want to add a wms-overlay to an existing openlayers-map on a website.
  The layer is stored on geoserver. When i open the layer on geoserver, it works just fine. 
  The data itself is in EPSG:31297.</p>
  
  <p>But when i load the website openlayers is empty. Although the layer is shown in the layerswitcher.</p>
  
  <p>I know there are a few questions concerning that topic, usually it had something to do with the project. However, in this case the projection should be fine. 
  I can't figure out why it doesn't work. </p>
  
  <p>Here is the code:</p>
  
  <pre><code>// My layer 
          var wms_layer = new OpenLayers.Layer.WMS (
              "Layer",
              "http://.../geoserver/wms",
              {
                  layers: "master:dauersied_2mio",                
                  transparent: "true",
                  projection: "EPSG:3857"
  
              },
              {isBaseLayer: false}
          );  
  
          map.addLayer(wms_layer);
  </code></pre>