Material Supply and Demand View Details in Cusom Business Object

Hello,

I have a Custom Business Object with Information from Material Supply and Demand View Object ( down part of Product Planning Details in Supply Chain Control -> Products). Information shown correct from last Planning run but the Document ID remains empty. Anyone an idea how to get the document ID ? For me it looks like it should be the BusinessTransactionDocumentID,but it isn't.

Thanks for your help.

Regards

Henning Ohlmeyer