I was able to get a version of JapserReports Server 5.2 compiled with the patch. download the JasperReports Server source, and the source files for the pptx patch, and use eclipse (or your java IDE of choice) to edit the source files so they compile. Use this guide here: http://community.jaspersoft.com/wiki/using-pptx-source-implement-within-your-own-environment
for the new files, it helps to compare them to the existing Docx files, the structure should be similar. If you have a good background in java development, you should be able to get it working (it took me about a week)