Change WMS CRS in cesiumJS

I´m currently working on a project where I need to embed a WMS, which doesn´t support CRS:84 but many EPSG Versions. Here is the link to the WMS, which I need to include (the service is not controlled from our side).

I´ve already changed the crs parameter of the WebMapServiceImageryProvider to EPSG:4326, but that doesn´t adjust the bbox parameter to the correct values.

I hope that someone could help me to change the CRS in my cesium project.

I´m happy for any help.

Solution

The Answer to my problem was to change the tilingScheme Parameter of the WebMapServiceImageryProvider to the WebMercatorTilingScheme.

new WebMapServiceImageryProvider({
    url: new Resource({
      url:
        'https://haleconnect.com/ows/services/org.868.3ece34f2-a7fc-4135-a1e6-a339add3142c_wms',
    }),
    parameters: {
      TRANSPARENT: true,
      STYLES: 'default',
      VERSION: '1.3.0',
      SERVICE: 'WMS',
      FORMAT: 'image/png',
    },
    tilingScheme: new WebMercatorTilingScheme(),
    layers: 'PS.ProtectedSite',
    crs: 'EPSG:3857',
  }),