Hi
1. Go to EDocman -> Dashboard, click on Option button in Joomla , select Registered Group, set Download Permission to Allowed. Then Select Public Group, Set Download permission to Inherited.
2. Edit documents, set "Access" field to Public
By doing that, all users can view these documents but only logged on users can download them. The only limitation in this case is that it doesn't display a message ask users login before downloading. I will consider adding support for this feature in future release.
Tuan