Copying Document Handling from one document to another document in Ax 2012

How to replicate the same document handling (File,Notes etc) from one document(Sales) to another document (Purchase).
Ex
If we want to show the Sales Document Handling Notes to Purchase Order, when we are creating direct delivery from Sales order to purchase order
then pass the following get the document handling

FromTable = salesTable;
ToTable     = purchTable;
Docu::copy(FromTable,ToTable);