Error pages/Web Authentication

[HTF]

Hello,

I would like to ask for some help.

1. Does Nginx support SHA encryption for the basic web authentication?
When I use -s switch with htpasswd command I can't log in. It works with
MD5 however it looks like MD5 has some character length limitation as
only the first eight characters are significant.

2. I have Joomla install running on Nginx. I enabled SEO URLs with
rewrite rule:
- try_files $uri $uri/ /index.php?q=$request_uri;
I'm facing the following issue:
Joomla has build in error pages. I've tested and I appended some random
characters within the URL:
a) http://mywebsite.com/random - and it shows Joomla error page which is
fine - same for http://mywebsite.com/index.htm however when I put
http://mywebsite.com/index.html it shows nginx 404 Not Found error page
b) When I type any random characters and append a file with php
extension at the end (http://mywebsite.com/random/index.php) there is a
blank page.

Is it possible to set this up so Nginx will show Joomla error page if
someone try to access not existing directory/file on the web server. 
Please note that I don't want to set custom error pages in Nginx config
file for now as this feature works fine with Apache - I can access any
not existing file/directory on Apache web server and it always shows
Joomla error page.

Regards

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,205299,205299#msg-205299