post https://rz3.aeb.de/demo1docs/rest/DocumentService/documentInstance///
Generate a new document instance.
Prepares a document immediately within response or asynchronously from the referenced document type and document data. The document type and reference object are resolved in the context of the session client. The output format and archive options are defined in the referenced document type. Created documents are retained for later reuse, e.g. fetching or printing the document. The caller can fetch the document contents by calling GET /document/{documentId} with the received documentId or GET /documentInstance/{referenceType}/{referenceNumber}/{documentType}. An existing document can be updated by specifying the reference object and stored as a new revision in the archive if it has to be or was previously archived.