[users@httpd] RewriteMap causing redirection loop

["Clodoaldo Pinto" <clodoaldo.pinto@xxxxxxxxx>]

I maintain a mediawiki site and I am trying to use short urls as explained here:
http://meta.wikimedia.org/wiki/Using_a_very_short_URL#Patching_Apache

Apache/2.0.53 (Fedora 3)

As my httpd server does not have the int:ampescape patch and I want to
avoid patching it I'm using a simple txt map file with this in
<VirtualHost>:

      RewriteEngine On

      # Don't rewrite requests for files in MediaWiki subdirectories,
      # MediaWiki PHP files, HTTP error documents, favicon.ico, or robots.txt
      RewriteCond %{REQUEST_URI} !^/(stylesheets|skins|images|config)/
      RewriteCond %{REQUEST_URI} !^/(index|redirect|texvc)\.php$
      RewriteCond %{REQUEST_URI} !^/error/(40(1|3|4)|500)\.html$
      RewriteCond %{REQUEST_URI} !^/(favicon\.ico|robots\.txt)$

      RewriteMap ampescape txt:/etc/httpd/conf/map.txt

      # This RewriteRule causes a redirection loop:
      RewriteRule ^/(.*)$ /index.php?title=${ampescape:$1} [L,QSA]

      # Works with this RewriteRule although obviously without the mapping
      # RewriteRule ^/(.*)$ /index.php?title=$1 [L,QSA]

The problem I'm having is that the browser gives me a message of
"Redirection limit for this URL exceeded".

Is using a txt Map the cause of the problem? Contents of map.txt:
&       %26

Regards, Clodoaldo