WFS from QGIS Server in OpenLayers 3

I'm trying to implement this example https://medium.com/@goldrydigital/wfs-t-with-openlayers-3-16-6fb6a820ac58 using QGIS Server (2.14) and adapted to a different SRS. Unfortunately the function ol.format.WFS.readFeatures() cannot read the geometry which QGIS Server sends back (see console.log(features[k].getGeometry()); // => NULL ))

Any help much appreciated, thanks!

BTW: When using an ArcGIS-Server-WFS, then the code below works correctly...

Code:

var formatWFS = new ol.format.WFS();
var sourceWFS = new ol.source.Vector({
            loader: function (extent) {
                $.ajax('http://xxx/qgis/qgis_mapserv.fcgi.exe', {
                    type: 'GET',
                    data: {
                        service: 'WFS',
                        version: '1.0.0',
                        request: 'GetFeature',
                        typename: 'test2',
                        srsname: 'EPSG:2056',
                        bbox: extent.join(',') + ',EPSG:2056'
                    }
                }).done(function (response) {
                        wfsresponsefeatures = formatWFS.readFeatures(response);
                                sourceWFS.addFeatures(wfsresponsefeatures);
                    features = sourceWFS.getFeatures();
                    for (var k in features) {
                        console.log(features[k].getGeometry()); // => NULL
                    }

The WFS Response is as follows:

    <wfs:FeatureCollection xmlns:wfs="http://www.opengis.net/wfs" xmlns:ogc="http://www.opengis.net/ogc" xmlns:gml="http://www.opengis.net/gml" xmlns:ows="http://www.opengis.net/ows" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:qgs="http://www.qgis.org/gml" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.opengis.net/wfs http://schemas.opengis.net/wfs/1.0.0/wfs.xsd http://www.qgis.org/gml http://szhm4120/qgis/qgis_mapserv.fcgi.exe?srsname=EPSG%3A2056&amp;SERVICE=WFS&amp;VERSION=1.0.0&amp;REQUEST=DescribeFeatureType&amp;TYPENAME=test2&amp;OUTPUTFORMAT=XMLSCHEMA"><gml:boundedBy>
 <gml:Box srsName="EPSG:2056">
  <gml:coordinates cs="," ts=" ">2681188.02,1246449.97 2685167.35,1248977.27</gml:coordinates>
 </gml:Box>
</gml:boundedBy>
<gml:featureMember>
 <qgs:test2 fid="test2.2">
  <gml:boundedBy>
   <gml:Box srsName="EPSG:2056">
    <gml:coordinates cs="," ts=" ">2683250.99,1248618.11 2683250.99,1248618.11</gml:coordinates>
   </gml:Box>
  </gml:boundedBy>
  <qgs:geometry>
   <gml:Point srsName="EPSG:2056">
    <gml:coordinates cs="," ts=" ">2683250.99,1248618.11</gml:coordinates>
   </gml:Point>
  </qgs:geometry>
  <qgs:id>2</qgs:id>
 </qgs:test2>
</gml:featureMember>
<gml:featureMember>
 <qgs:test2 fid="test2.3">
  <gml:boundedBy>
   <gml:Box srsName="EPSG:2056">
    <gml:coordinates cs="," ts=" ">2681673.03,1247121.49 2681673.03,1247121.49</gml:coordinates>
   </gml:Box>
  </gml:boundedBy>
  <qgs:geometry>
   <gml:Point srsName="EPSG:2056">
    <gml:coordinates cs="," ts=" ">2681673.03,1247121.49</gml:coordinates>
   </gml:Point>
  </qgs:geometry>
  <qgs:id>3</qgs:id>
 </qgs:test2>
</gml:featureMember>
<gml:featureMember>
 <qgs:test2 fid="test2.6">
  <gml:boundedBy>
   <gml:Box srsName="EPSG:2056">
    <gml:coordinates cs="," ts=" ">2682779.23,1248227.69 2682779.23,1248227.69</gml:coordinates>
   </gml:Box>
  </gml:boundedBy>
  <qgs:geometry>
   <gml:Point srsName="EPSG:2056">
    <gml:coordinates cs="," ts=" ">2682779.23,1248227.69</gml:coordinates>
   </gml:Point>
  </qgs:geometry>
  <qgs:id>6</qgs:id>
 </qgs:test2>
</gml:featureMember>
</wfs:FeatureCollection>

okay, so QGIS Server can only serve WFS 1.0.0 with GML2-geometries...

the above example works by setting the WFS to GML2

var formatWFS = new ol.format.WFS({
    'gmlFormat': new ol.format.GML2
});