Как правильно прописать правила .htaccess, для того чтоб подменить URL?

[26/Jul/2014:19:24:50 +0400] "GET /admin/ HTTP/1.1" 404 15496 "-" "Mozilla/5.0 (X11; Linux i686) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/33.0.1750.152 Safari/537.36" "-"
[26/Jul/2014:19:24:50 +0400] "HEAD /admin/ HTTP/1.1" 404 0 "http://domain.com/admin/" "Mozilla/5.0 (X11; Linux i686) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/33.0.1750.152 Safari/537.36" "-"
[26/Jul/2014:19:24:50 +0400] "HEAD /admin/ HTTP/1.1" 404 0 "http://domain.com/admin/" "Mozilla/5.0 (X11; Linux i686) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/33.0.1750.152 Safari/537.36" "-"

<FilesMatch "\.md5$">
    Deny from all
</FilesMatch>

DirectoryIndex index.php
Options -Indexes
# Comment the following line, if option Multiviews not allowed here
# Options -MultiViews

AddDefaultCharset utf-8

<ifModule mod_rewrite.c>
    RewriteEngine On
    # Uncomment the following line, if you are having trouble
    # RewriteBase /

    RewriteCond %{REQUEST_URI} !\.(js|css|jpg|jpeg|gif|png)$
    RewriteCond %{REQUEST_FILENAME} !-f
    RewriteCond %{REQUEST_FILENAME} !-d
    RewriteRule ^(.*)$ index.php [L,QSA]
    RewriteRule ^admin/(.*) /webasyst/$1 [L]
</ifModule>

<ifModule mod_headers.c>
    <FilesMatch "\.(jpg|jpeg|png|gif|js|css)$">
	Header set Cache-Control "max-age=3153600, public"
   </FilesMatch>
</ifModule>

...
RewriteRule ^(.*)$ index.php [QSA]
RewriteRule ^admin/(.*) /webasyst/$1 [L]
...