I created this short movie that shows how to insert an AUTOCAD DWG's filename into the file.
The AutoCAD command to be used (if it is not clear at in the video) is "FIELD"
This came from a case where a customer was using a Diesel Expression to display the filename. This worked, to some degree, but the problem arose when they tried to publish the DWF within Vault or by using the Job Server. Instead, it displayed some of the diesel expression instead ($(GETVAR.??)).