Link to PDF File
In the various DM schedules (light fixtures, receptacles, diffuser, etc), add the option to link the entry to a PDF file. The PDF could be opened from the schedule, or there could be an option to include it as a hyperlink on the device so it can be opened from the AutoCAD drawing.
Aaron Dennington commented
A simple "Attach" button that allows the user to browse for a file to attach to an equipment connection, receptacle type, or light fixture definition. The file would often be used to attach a pdf cut sheet to that particular piece of equipment and would be very helpful in keeping track of the source information used to create the equipment, receptacle, or fixture definition.