* The method defines custom properties for PDF document meta data. The method takes effect only in PD4ML Volume DMS and PD4ML SRC license binaries.
* @param key a unique name, which must not be one of the standard property names Title, Author, Subject,
* Keywords, Creator, Producer, CreationDate, ModDate and Trapped
* @param value data itself
* @param hide makes the metadata not appear in the PDF document properties dialog of Acroread
public void addMetadata(String key, String value, boolean hide) {

There are dedicated API methods pd4ml.setAuthorName() and pd4ml.setDocumentTitle() could help you to workaround.

Also you can try to post-process generated PDFs with PD4Document/PD4DocumentBase API.