I tried to create password protected directory using the Control Panel. But when directory is "ON" i.e. password protected link though wordpress doesn't work - It says "not found". When password disabled - all work ok (downloading pdf). I need that wordpress allows follow link to a protected file but with asking a pass login etc installed in CP. I mean that wordpress allow CP's protected directory work.
P.S. Yes, I know that they are different systems and before I tried to protect a file by WordPress plugins like UAM etc. but smart people started to download the file directly bypassing the WordPress :)