1. Do not support Russian file names on server (note: it works as expected, puts correct file names to users, but stores its on server in krakozyabras ;)). I prepared my changes to fix it, tried to send it to developers, but was unable to register on site (tried twice), have got "Could not get user" error message after the validation.
2. It seems like plugin eats quotes in file description while I tried to edit the description with quotes.
But anyway, thanks to developers.
As described in the help page, Attachments handles special characters better if you use the "Secure" mode (see under the "Security" tab in the Attachments options). Unclear what the second issue is about.
Feel free to contact the developer any issues with Attachments and any suggestions or code fixes! The developer's email is available at the end of the Attachments help page.