For anyone still looking through this thread, the following S3D script will upload the file to your printer (with a timestamp) and tell it to start printing that file much like Slic3r would do:
curl -F "file=@[output_filepath]" "http://XXX.XXX.XXX.XXX/rr_upload?name=gcodes/[output_filename].gcode&time=YYY" curl "http://XXX.XXX.XXX.XXX/rr_gcode?gcode=M32[output_filename].gcode"
Copy and paste into "Additional terminal commands for post processing" under the Scripts tab and replace XXX.XXX.XXX.XXX with your printer's IP address or hostname if applicable. As mentioned above, DWC will throw a couple of errors but doesn't seem to impact the print in any way. Happy printing!