IBM-ODIndexes "wrapper" missing in PDF

I need to add PPD search keys in a PDF document for archival to IBM CMOD.

Using Exstream 16.4 I created a new test application, added As-is search keys and added them individually to the controlfile switch.

According to article KB0719890 there should be a /IBM-ODIndexes included as header with the search keys underneath.

The generated PDF contains the actual search keys correctly but the IBM-ODIndexes part is missing.

Any advice?

/PieceInfo <</IBM-ODIndexes <</Private
<<
[Your search keys will be placed here]