MapFish print module with cql_filter params

Question

Does anyone know how to pass cql_filter params into MapFish's Print module? I already tried this, but it does not work. It generates the PDF but I get this error "The byte array is not a recognized imageformat. ":

{
  "units" : "degrees",
  "srs" : "EPSG:4326",
  "layout" : "A4 portrait",
  "dpi" : 75,
  "mapTitle" : "Printing Demo",
  "comment" : "This is a simple map printed from GeoExt.",
  "layers" : [{
      "baseURL" : "http://zzz.com:8080/geoserver/wms",
      "opacity" : 1,
      "singleTile" : true,
      "type" : "WMS",
      "layers" : ["zzz:yyy"],
      "customParams" : {
        "CQL_FILTER" : "dico in('1106')"
      },
      "format" : "image/jpeg",
      "styles" : [""]
    }
  ],
  "pages" : [{
      "center" : [-9.157682, 38.741626],
      "scale" : 4000000,
      "rotation" : 0
    }
  ],
  "legends" : [{
      "name" : "Tasmania",
      "classes" : [{
          "name" : "",
          "icons" : ["http://zzz.com:8080/geoserver/wms?SERVICE=WMS&VERSION=1.1.1&REQUEST=GetLegendGraphic&EXCEPTIONS=application/vnd.ogc.se_xml&LAYER=zzz:yyy&FORMAT=image/gif&SCALE=4000000"]
        }
      ]
    }
  ]
}

Answer 1

Assuming that you are running GeoSolution's fork of Mapfish then the code you have there will work. So I would suspect that there is some issue with your setup as even if you are running the stock set up all it does is ignore your CQL Filter.