In the Actions panel, select “Export any activity file attachments on to the DAD object?”.
The AE export window BEFORE the export has been run is below.
The AE export window AFTER the export has been run is below.
You can see the green icon to indicate that the file was copied across succesfully.
You will also see a message informing that this activity has found its linked component in the digital model.
If you open the DAD application you can see the attached file by opening the objects “Data & Attachments” window.