Aspose-pdf library - create a many in one pdf file

Hi,

I work with the java version of aspose library, JRE 7, Windows 7.

I'm using the last version of aspose pdf library (4.3.1) which merge the two precedent versions of apose pdf and aspose pdf-kit, and I try to put many (4 in 1 for example)  pages in one page. As a result, I get a new empty pdf file.  

I didn't encounter this problem with the version pdf-kit 4.6.0.

Is there a problem with this this functionality ?