Rails - Jul 2006 - Use mod_rewrite rules instead of rails-routes

Hi
I am trying to use mod_rewrite rules instead of rails routes (don''t ask
why.., routes are not flexible enough in my case):

Basically I have these two RewriteRules in my .htaccess file:

RewriteRule ^(.*\/)*index\.([0-9]+)\.([0-9]+)\.html$ 
/keywords/show?id=$2&page=$3
RewriteRule ^(.*)$ dispatch.fcgi [QSA,L]

So I want /foo/bar/index.123.4.html rewritten to 
/keywords/show?id=123&page=$4 for rails.

Using apache 2.2.2 and mod_fcgid, rails recognizes the original uri 
"/foo/bar/index.123.4.html".
>From the rewrite log I can see that the rewriting process is also not 
done correctly:

applying pattern ''^(.*\/)*index\.([0-9]+)\.([0-9]+)\.html$'' to
uri
''foo/bar/index.123.4.html''
rewrite ''foo/bar/index.123.4.html'' ->
''/keywords/show?id=123&page=4''
split uri=/keywords/show?id=123&page=4 -> uri=/keywords/show, 
args=id=123&page=4
add path info postfix: /keywords/show -> /keywords/show/bar/index.123.4.html
applying pattern ''^(.*)$'' to uri
''/keywords/show/bar/index.123.4.html''
rewrite ''/keywords/show/bar/index.123.4.html'' ->
''dispatch.fcgi''

This "add path info postfix" should not happen, it rewrites the url to
/keywords/show/bar/index.123.4.html (which finally rails does even not 
recognize)

Using apache 1.3.33 and mod_fastcgi I get the same rewrite log, but 
rails shows now a 400 bad request error...

How can I use mod_rewrite with rails?

TIA, Tobias