Ken Ottmann on "[Plugin: WP-Filebase Download Manager] Adding a Social Content Locker Plugin?"

I found a solution by adding the wp-social-locker plugin and locking the downloads with a shortcode.

To do so I changed the file attachment from ID-based to manual shortcode.

Sample for a locked file in an article:

[sociallocker][wpfilebase tag="file" id=1 /][/sociallocker]

http://www.kenottmann.com/category/downloads/