Modifying DITA Open Toolkit Build Files for CSH
http://www.hyperwrite.com/Articles/showarticle.aspx?id=67

Self, Tony
HyperWrite
2008

Abstract:

This procedure is used to modify the DITA Open Toolkit build files to allow an external map file reference and alias strings to be added to the HTML Help Project file before building, as part of the transformation to Microsoft HTML Help (CHM) format.