When adding representations via the 3A workbench, the default procedure is the applet upload. Due to security settings, the applet may not be available in some environments. In this case, the user has to click the "Load the files manually" link located on the left to then switch to the manual upload procedure, which works fine.
To avoid these extra steps it would be nice to set the default upload procedure (applet or manual) for 3A workflows via a general parameter.