Adding custom metadata to PDF

[Miurath]

Is it possible to add custom metadata to a .PDF with BIRT?

I have found how to set one of the core meta data via org.eclipse.birt.report.model.api.ModuleHandleImpl#setAuthor for example, but I cannot find a way to set non-core metadata data.

[hvbtup]

I don't think this is supported.
But if you control the process, you could use the following approach:
Put the data you want into the appContext from inside your report.

After BIRT has finished creating the PDF, use OpenPDF (which is included as a library with BIRT) to modify the PDF any way you like, eg. adding XMPMetadata or (what I do:) add page numbering based on the TOC (outline) structure.