Exporting Report to PDF - Report Application Server 2013

I am trying to export a report to PDF format by using the following code:

ByteArrayInputStream byteArrayInputStream = (ByteArrayInputStream) clientDoc.getPrintOutputController().export(ReportExportFormat.PDF);

This code works when using the XI version of the Report Application Version. However, I am recently upgrading to 2013 and when trying to export I am getting a java.lang.ClassCastException

I tried to search for the API Reference and Developer Guide for the 2013 version, however I couldn't find it. The most recent version that I could find is the 2011 version.

Could you please guide me with a sample of how an export is done and do you have any links for the API Reference and Developer Guide for the 2013 version?