Enable POST and PUT commands with a body when calling REST Web Services

com.sos.jitl.restclient.JobSchedulerRestClient.headers.put("Content-Type", "application/xml");
  var post = "post(<resource><ID>4711</ID><LASTNAME>world</LASTNAME><FIRSTNAME>Hello</FIRSTNAME></resource>)";
  var s = com.sos.jitl.restclient.JobSchedulerRestClient.executeRestServiceCommand(post, "http://arestservice_url.com/sqlrest/CUSTOMER/" );