GeoServer S3 Support for GeoTIFF REST-API

I am stuck with S3 Support for GeoTIFF while I add a dataset with the REST-API.

I did not find any documentation for the REST-API… so I tried to edit my local API-POST-Call:

<coverageStore>
  <name>NameOrtho</name>
  <workspace>NameWorkspace</workspace>
  <enabled>true</enabled>
  <type>GeoTIFF</type>
  <url>s3://bucket/DEM.tif?useAnon=true&awsRegion=EU_CENTRAL_1</url>
</coverageStore>

But this returns:

---- Debugging information ----
cause-exception     : com.thoughtworks.xstream.io.StreamException
cause-message       : 
class               : java.lang.String
required-type       : java.lang.String
converter-type      : com.thoughtworks.xstream.converters.SingleValueConverterWrapper
wrapped-converter   : com.thoughtworks.xstream.converters.basic.StringConverter
line number         : 6
class[1]            : org.geoserver.catalog.impl.CoverageStoreInfoImpl
converter-type[1]   : org.geoserver.config.util.XStreamPersister$StoreInfoConverter
version             : 2.15.0
-------------------------------

What should I do?